Hey Rob-- I just got one of those bags about 2 weeks ago, and I must say that so far it is STELLAR! Finally someone built a real backpack for hauling photo gear, rather than a photo bag with backpack straps on it.
I was out west in Colorado hiking with all my gear, plus an off cam strobe and battery pack, extra clothes, water, and snowshoes strapped to the pack. Probably 50 lbs give or take. It was very comfortable and well balanced for me. I am 6'2" so most of the time packs are too small for me, but this fit perfectly. I am looking forward to many more adventures with this pack. The only drawback I have found is that it the area for a hydration bladder is a little awkward, but maybe I just need to find a different baldder.
Incidentally, I had orderd a different Clik pack first, but it was too small for my gear. called them campany and talked with a real person--Jim--for about 30-40 min. He was very nice and extremely heplful in helping me find what I was looking for.
You will love your new pack!