I have a '05 FE550 and have never had any problems with it. I did go to a different needle (NCVR - Yamaha part # 5TA-14916-VR-00) and pilot jet (55). With this jet combination it always starts real easy and pulls real smooth right off idle. The bike is a real blast to ride and I like the handling way better than the 4-stroke KTMs I've owned in the past and I think it turns better than my KTM 200XCW. My history with Husabergs goes back to the mid '90s with my '96 FE501 and back then they were a bit on the crude side but by '05 they are as refined as the KTMs, etc. Also the '05 models do not have the potential reliability issues of the earlier ('01-'04) motors and by then have the Keihin carbs and much better ignitions (I once had a '02 FE650).
The main thing to keep in mind with it is to change the oil regularly (I do it every 5 hours or so) and make sure the valves are adjusted properly.