I rode a 2013 RIP9 - I ended up with the aluminum version - I wanted to try the RDO (carbon), but it was out when I stopped by. I was VERY impressed by the RIP - I have a 2010 RIP and the bike I rode was like my bike on steroids. I felt instantly comfortable and rode it hard with no weirdness at all, the weight difference was highly noticeable, although I'm sure some of that (a lot of it) was in the carbon wheels. Without having tried a lot of other bikes I'd buy another 2013 RIP9 right now, no questions asked.
I also tried a Rocky Mountain 5" 29er (can't remember the name). I disliked that bike. I never felt comfortable on it - maybe it wasn't set up correctly for me, but it was an eye opener after riding that RIP, it felt completely XC whereas my RIP always feels like I'm not worthy of the bike, someone more skilled could push it so much harder. No offense, but the guy who set me up on the RM was slow, he drove me crazy walking about seemingly aimlessly while I waited for the bike.
I wish I got to try more bikes, but in the end I opted for riding time over standing in line/filling out forms/getting a bike set up time. When I can afford a new bike I will definitely use a demo set up like this to help me make my choice. It was just idle curiosity right now.