Very good. I've got the DP version (TE610), and it's really fun on tight and twisties. About 50 rwhp, 324lb fully gassed, so it's relatively quick out of corners.
Don't expect to run high speeds, the aerodynamics suck compared to a sport bike.
Really quick to flick into corners, makes a 600 feel overweight.
The stock saddle sucks though...
Go to
www.thumpertalk.com, there is a Husky forum. There also a few SM forums (fora in real English / Latin...), where a number of the members are on 610s. Search Thumpertalk, should be links to them.
Also, the Thumpers forum on advrider.com has some very useful info, especially for the TE (same basic bike).