I handled one at the store the year they came out. I had ready everything about them and was excited to see it. I was overly disappointed. Frame was flimsy and bag put together oddly with pocket configuration. Just my thoughts though. Although I have never known anyone personally that uses one.
I was actually looking hardcore an buying one but to be honest at $399 you can save another 100 and buy kifaru. It's seems like a good idea and Steven Rinella sure does swear by them. I tried to find someone who had experience with them but it was a no go. Maybe more people do in Arizona where there made. Nice product made in the USA though.
I looked at one at a show last year. They look well built. I thought the frame had a little to much flex in it. But other than that I liked the external frame for heavy loads. There is a similar pack looks like the same frame that western pack specialities makes. I don't know if they are just using the same frame or what. The frame has about the same amount of flex as a 2011 KUIU ICON had before the revamp.