Brian, I actually never imagined I'd be using the bag quite like this. For one, there's a lot more space that what the listed dimensions make it sound like. I was originally only looking for an EDC bag that could fit a small DSLR body + walkaround lens, maybe a filter and spare battery pack, along with the usual crap I lug around: cell phone, glasses, keys, wallet, often times my PDA and a water bottle.
It turned out, of course, that the Jumbo can carry way more than that. I'd previously been using an SDS 3-day assault pack, and everything I was carrying fit into the Jumbo, which is both more convenient and way less conspicuous.
For what I do with it, I haven't had any problems with the bag bumping into anything and if I find it necessary to stabilize the bag I'll attach it to a rigger's belt, which I sometimes wear when I have my dog with me (I have a carabiner on the leash which I attach to the belt so he doesn't wander or anything, and it keeps my hands free).
The Colossus does look interesting, definitely something to keep in mind if I need more space or padding. So far the Jumbo beats any camera bag I've used, including a Lowepro slingshot 200 (I wanted it to do what the Jumbo does, but it didn't -- plus it was bulkier and carried less), so I wouldn't hesitate to get another Maxpedition bag. Most people seem to think it's a really cool looking bag, too.