I really really wanted to like this bad, and I tried every way I could to make it work. In the end, I had to bite the bullet and return it, and continue searching for a new travel backpack, and sacrifice the built-in safety features. The colors (I bought the blue with the lime green interior) is perfect, and I really will miss that as well. I am a 5'9" woman with very broad shoulders for a woman, so please keep that in mind. All of the safety features are great, and I test-packed the back, and found the following problems when the bag was loaded with stuff:1) The backboard of the backpack is VERY stiff- this will not bend, but that does mean better support. However, it is also about 1.5" too long for comfort with this stiffness. With the limited shortening of the straps (more later) I needed to have a little give in the bottom of the backboard to stop it from painfully rubbing the back of my hips. This would have been extremely painful with travel, and would have not only resulted in wearing out shirts and pants (I've experienced similar problems with backpacks rubbing in other areas before), but also irritating the skin or even leading to blistering from the friction. Unfortunately, there is no way to adjust the length of the backboard except by shortening the straps....2) The straps have limited ability to shorten due to their cabling safety feature. I think the cables are awesome, and the straps adjust from the shoulder of the bag so the cable runs all the way up the strap. However, there is a part on the strap where the cable ends and the pull-strap part begins, and this is stitched such a way that it will not feed through the adjusters. I completely understand why, but it means you can't shorten the straps. I thought this wouldn't be an issue for me, as I normally like my straps longer, but paired with the stiff backboard it was a serious issue. The usual length I would keep the straps at was not comfortable at all with the stiff back, and I progressively shortened them, improving the comfort every step of the way but hitting the limit too soon. Again, this wouldn't have been a problem without the stiff backboard, so (1) and (2) are very related.3) The weight in the bag is all carried at the base- its how the shape of the bag is designed, with a wider base and a tapering of the depth as it goes up. Its not illogical, but it does mean that the bag will stick out a lot in one spot, and that makes it harder for me to move in crowds or turn around without hitting people or knocking things.4) The smaller front pocket, where you can keep small items, only zips along the right side and the top, and about an inch along the left side. Normally, no problem- most right handed people zip that way. however, I am left-handed, and I prefer to zip from the left. This only really matters when I don't have the zippers locked for security, as the lock is only on the right side, so I would have to zip that way then. But making it zip equally down each side would just have made that pocket a lot easier to use, as would having the zipper clip locks on both sides of the bag for us lefties to use.Otherwise, i really liked the bag. Good construction, well built, and everything I have come to trust from PacSafe. I would have liked to see compression straps on the 15L version- I would have considered buying that one instead. Or, alternatively, perhaps a 20L version with compression straps instead- this would have been the most ideal size of still being spacious but more compact and less intrusive. But, oh well.I think this bag would be very good for men, as they normally don't have much curve below the waist at the top of the butt, and so the rubbing wouldn't be much of an issue. Also, taller individuals because of the need for short straps on this and the limiter. However, with Amazon's easy returns, you can always try it out and send it back if it doesn't work like I did. Who knows, you may find its the bag for you afterall!This was a great addition to my traveling equipment. So nice to know that in crowded places I can feel confident that no one can easily pick pocket my backpack or slash and run.It takes some effort to secure the zippers but it soon became easy to do. Overall a nicely made pack and very comfortable to wear. Could use some additional inside compartments, but I highly recommend.I specifically purchased this bag as it appears to meet United Airlines personal item requirements (January 2022). Every other backpack I previously used to seems to be grossly oversized per their requirements. There were cheaper $20/$30 options available on Amazon, but the quality is evident with this bag. The materials are thick and the security features are nice. This is a great lightweight backpack that fits a lot of necessary items for a day or on a plane. It can fit a 14” laptop if needed as well. I expect this will last a long time (unless the airlines change their requirements again).I like this backpack a lot except for one problem that is particular to me, which I'll explain later, and would give it 3.5 stars if possible. It is well made with great security features, is lightweight, and its dark blue color with lime green accents is a nice change from the traditional black/dark gray backpack. The inside lining is lime green with a gray abstract design. The gray, outside, side pockets/trim are a shade or two darker than it appeared online (at least on my laptop), so it will show dirt/grim less easily. There is a jack (a small opening) at the top of the bag for your headphones. Overall, the backpack looks nice for either male or female.My MacBook Pro fits securely in the padded internal sleeve, the only pocket inside the bag other than the main compartment. The zipped pocket on the outside front is just under 13" in length and 8" in width. Inside are 2 small pockets, good for carrying metro cards, change/money, passport etc. Both pockets may be RFID protected as the lining feels the same, but only one has the label on it. That pocket has a Velcro flap to secure it. There is also an elastic pen/pencil holder. Both the main and front compartments have security zipper clasps to prevent the backpack from being easily and surreptitiously unzipped. One of the shoulder straps unhooks and can be secured to stationary items for safekeeping. I am able to fit a lot inside (my DSLR camera, several books, etc.).My mom purchased this backpack for me for use during a 3-week European study tour in May 2014. It served as a perfectly-sized carry-on during air travel, but other than that I didn't use it much because she also purchased the Pacsafe Luggage 200 Gii Handbag, which worked better for my needs and was more comfortable.Now for my issue with this backpack....I am a 5'8, medium-built woman who likes my backpacks to fit snugly and not move around much as I walk/move, especially when carrying heavy books as I did during my tour. The adjustable shoulder straps do not tighten enough to accomplish this, so the backpack jostled a lot for my taste, even when using the two waist/chest security straps. As a result, the molded back padding was uncomfortable. Other than this issue, I plan to use the backpack during the next school year as I think (hope) that carrying a lighter load will make it more comfortable.I've had pacsafe manbags for nearly 20 years and thought it was time to get a city backpack with similar security. I have a man bag because I don't like pockets. Pockets were ok when i carried a wallet and a paperback, but now I have a phone, a million keys, reading glasses, shades, brolly, headphones etc.I live in London and have more recently been using a backpack more than my manbag. Problem with a back pack is it's behind you when you are on the tube, in Leicester Square, walking the West End, but I still don't like keeping my valuables in pockets. Also I like to go on city breaks to beautiful (and dodgy) European cities.This is the solution. I hesitated because it's not cheap and I couldn't try it on. Would it be comfortable?Well yes it is. Go for it. Obviously there are different sizes and so on with pacsafe but this is about 25l and so a perfect size for all things, I think. The zips lock and there's a metal mesh inside so you can get on the metro in Athens and not worry about it being picked or slashed. I find it comfortable to wear, but I don't use the waist strap. I should point out that the shoulder straps are not easy to adjust. This is to do with the security features. Definitely not a deal breaker.After a battle with Amazon to get this delivered, it finally arrived. Beware of the emails that say it is out for delivery. You have no way of checking where it is. This was still in the depot at 9pm despite being told at 8pm it was on the way. Amazon ,you need to sort this out!!The product is just what I wanted and will make carrying your more valuable items a little safer when out and about. It is very light despite the cables in the straps and mesh in the fabric. Enough room for an SLR camera, sunscreen, water and some food. The zips look sturdy enough and can be locked together as well as using the hidden clip. I saw some comments about the strap clip being poor quality. It is not plastic, it has a plastic cover in the vee to save wear and tear. It looks fine to me and I used to be a fitters mate on engineering. I would be quite happy to leave this strapped to a table or railings.Yes it is expensive for a small rucksack. However, you are likely to be carrying money, cards, passports cameras and tablets. How much do you value these? Not been used as yet but will update when I return from Barcelona.Update 23rd July: Have now used several times and I am very pleased with it. It holds all I want on a day out and keeps my hands free for camera work. I like the way the strap detaches to secure to a table or immovable object whilst in a restaurant or in a park or on the metro. Deters driveby snatches if securely on both shoulders.Straps are knife proof and the RFID pocket protects your passport and cards from data theft. Expensive? Yes a bit, but I am glad I paid the extra.Awesome bag, plenty of space inside. very good outer pocket/pouch organised interior pockets (interior of outer zipped pocket).The main interior section could do with some velcro partitioning walls to give an option of sectioning off a small part to keep stuff from moving around (the space is large and unencombered, i refuse to wrap stuff in towels to keep them from moving about when i am out / as well as the additional weight of the padding that i would need to use). - will glue/fit/stitch some myself no worries.This bag is an average (standard/middle of the road) size.I dislike the padded back 'plate' (that rests on your back) a middle channel for airflow would be of great benifit to its design. Hence why it loses a star.Glad i took a gamble on the bag size, as a litre measurement is best left for proper camping bags and car boots, and the product description/name conflicts with details, its either a 25Lor an 11L, make up your mind ;)To future purchacers: it is a standard backpack size. (slightly deeper than standard).Bought for a trip to Europe as I was concerned about safety. This has now become my daily bag and is my top buy of 2014! Features external side pockets for brolly, and other stud (apple, water bottle...)and security features that are excellent. When travelling I fitted an internal water bladder that was brilliant as I needed more water for myself and my partner than one litre). This fitted into the inner rear sleeve that now houses my iPad. There is enough space inside for daily needs - when travelling that might include a light jumper/top and rainwear. I was surprised at how much it holds, and how comfortable it was. The straps are a unique and very adjustable feature. At first I could not figure it out but after 15 minutes of playing around managed to get a perfect fir and a method of getting the bag on and off really simply. I am very pleased with this bag and recommend it!It's suitable for carrying small to medium items, main compartment is just about big enough to fit my fleece and 13inch laptop. Pockets are plenty and internal organiser pockets are very useful too with a plastic carabiner for keys. I feel secure using it knowing it can deter would-be thieves. I see this more as a basic little brother version of the much 25l rucksack which I also own. Also has an earphone port. Only disadvantage I can think of which isn't a huge issue but the back bit of the bag where the straps are is a little hard but thats only because of it's security & ergonomics, might be uncomfortable for some though so I have given it a fair four stars.