OK, So recently I got a bike. Yes, it's a fixie, and I'm really digging it, actually...
It's different. It's got a seat belt buckle (YES, from a car, hilariously...), so you never have to adjust the strap to a point where it's too loose just so you can take it off. Instead, you always keep it tight, and just unbuckle to remove. Brilliant, because that was ALWAYS the problem I had with the Crumplers and other laptop bags. They always hung loose and swung about, invariably causing sideways stress against your shoulder. After an entire day, it's brutal. Instead, the bag is meant to be worn tightly and high up on your back, like so (best when worn in your trendy warehouse live/work loft, as shown below):
Snap. Much better for walking around. Much better for getting around town on a bike. And very compact -- it holds surprisingly a lot for such a small package. I fit my 15" macbook pro AND my Canon 5D with 35mm f/1.4L lens, with power adapter, and there was still spare room for a change of clothes. And with the new ergonomics of the bag slung high against my back, I can now wear it for hours without the same wear and tear that I experienced with the Crumpler. If you're in San Francisco, it's probably worth checking out their store on 4th and Brannan, actually! They even gave me a free 15" laptop sleeve, since the ones for the Macbook Pro aren't coming in for another few months. Really cool store, chilled out vibe and helpful salespeople. I'll keep my Crumpler because it seriously will hold the kitchen sink and then some... but I think when all I need is a computer on my back and I'm out and about, I think I have a new favorite bag.