I bought this bag approximately 5 months ago, and I've used it every day to haul my laptop on a 2 hour commute to my school via walking/public transportation. Of all the backpacks I've ever owned, this is the absolute best.
There is plenty of padding to protect my laptop from bumps and falls. The material of the bag is exceptionally good at keeping the contents dry during rain and snow. The inside is also very roomy, so I store my laptop, a couple of notebooks, and a book to read inside, and I use the outer pockets for pens and notepads. After 5 months of constant use, absolutely no wear is visible on the bag, which is awesome.
Recently, I've rigged my laptop's power adapter in the bag, and now the bag has become a portable workstation. The material is very breathable, so poor ventilation isn't a concern. Now, when I use my laptop in class, all I have to do is flip open the bag, plug in my laptop and start it up. So easy!
The backpack is also convertible to a more traditional laptop case, by tucking the shoulder straps into a specialized compartment. You can then carry the bag via one of the handles on the sides. I personally wear mine as a backpack, but it's totally up to personal preference. As far as the backpack mode goes, the weight distribution is excellent. Sometimes I completely forget that I'm wearing a backpack, which just goes to show the comfort level is great.
Just make sure you take careful measurements of your laptop before you purchase this pack.
Fits everything I need for school.
Very comfortable to wear (Has a nice weight distribution).
Shoulder straps have a velcro stop-tab so they don't come loose.
None that I could find.