I tried out the R320 today at PRG. They have a size medium to demo (just barely small enough for me--I have a 28" waist).
I have to say it was pretty comfy. It seemed like it would pack quite small, which would be nice for trips into the backcountry. The gear loops have a vinyl cover which you can switch to angle either forward or backward, or even leave off (nice if you're gonna wear a pack).
Gripes: obviously, cost. Also, the "haul" loop is a total misnomer. I'm not sure I would trust it to hold much weight, and there's a plastic (!) ring through it; why not a lightweight aluminum one I'm not sure.
Overall seemed pretty slick.