Pros: Crisp handling, super responsive, great on climbs, eats up roots and rocks, descends like crazy, great components and price point
Recommendation: This bike is awesome! Super reactive, all you have to do is think about turning and it feels like the bike does it for you. Nimble ride, corners like a beast, leans over smoothly and pops back up on the other side. This is my first full suspension (lighter than my hardtail!) and climbing is not an issue, minimal bob on the way up, and flies down the other side. 29 inch wheels eat up the trails. Seriously, there is no down side to this bike.
Recommendation: I was riding a 2005 Stumpjumper. My new Hi Fi is a much more stable ride and climbs over roots and helmet sized rocks way better than the stumpjumper while handling nicely. It's a little heavier, but seems to be a much better bike. Brakes and drivetrain are working perfectly after numerous rides through snow, ice and mud.
Pros: Stiff, efficient, climbs well and descents like crazy. It also handles tight spots much better than one would think a 29er would and all for a price that won't break the bank.
Recommendation: I had a 2008 Gary Fisher HiFi Deluxe 29er that I loved until I test rode the new one. Trek/Gary Fisher and made a ton of improvements in the 2011 model which will run circles around the 2008 and 2009. It rides and handles like a bike that is much more expensive yet they have kept the price down to a level that more folks can handle. If you want a great do all bike then buy it you won't regret it.