I've had this bike for several years, have taken it on some pretty tough trails and it has stood up to everything. Haven't Broken anything major and the bike is Wicked LIGHT! Very comfortable frame. Best thing I did was add Bontrager saddle and suspension seat post.
I just bought this bike a week ago and have taken it on some hardcore mountain trails as well as flat gravel trails. Overall it's a great buy - sold frame, good components, and made in USA! Rides well on gravel/paved trails, and also can take a good beating on rockier trails. The shock works well, with a lock-out setting available for riding on flat ground. I also tried the trek 4900, gary fisher tassajara, specialized rockhopper, and I felt this bike beat them all (though a little more expensive).
This is a great entry- to low intermediate-level hardtail. For about $800, you get a quality Cannondale frame, Shimano Deore shifters and front derailleur, Shimano Deore XT rear derailleur, and Cannondale's Headshok Fatty Ultra DL. Other components are average - use them until they wear out, break, or you find some extra money. I'm guessing I'd most want to invest in some new wheels and maybe some disk brakes. The saddle was to hard for my butt, so I upgraded to a Specialized BG Comp saddle.
The bike comes in two colors: Orange and Denim Blue. Cannondale seems to feature the Orange version in its catalog and on its website, but I really think the Denim Blue is a terrific color. It is a really rich, dark blue - not quite a midnight blue. It really does remind me of denim - kind of like one of J. Crew's darker pairs of blue jeans.