My larger thoughts are that bear spray is poorly designed. It's fragile, hard to secure, the safety is uninspiring, and if it inadvertently goes of, the consequences are bad.
Bear spray in the pack does little good, but it's hard to secure it where you can get it fast, and where it won't fall off, and where the safety won't get pulled on in brush, and where it won't get banged around in daily use. I had the plastic head of a can randomly fall completely off earlier this year, thankfully with no ill effects.
So until a pro-model comes out that fixes these, I compromise by keeping it on the belt at times, and in the pack at others (e.g. during the scramble up chimneys that got me to the bench in the video). Not ideal, but the best I can manage at the moment.
The pack has been a great design. More pics here: http://bedrockandparadox.com/2012/06/14/the-610-pack/ I swapped out the OMM straps in those original shots as they rubbed my neck.