I'm a MT Biker who just bought one ("05" R660) 4 weeks ago for $899 with $100 rebate with a Performance Card. I've put on 650+ miles on it since then. The Kenda tires are garbage, they only lasted 400miles as stitching started to show with 2 flats. I now have Michelin Krylion Carbons. I had a minor problem when climbing standing up, the rear tire would rub on the brake pads. I thought it was the frame flexing too much but all it was is I just had to tighting the rear skewers. All is good now, no more rubbing. I also changed the Truvativ Crankset to FSA Carbon Compacts as I wanna do more climbing for MTB training.
As far as the bike, it's 17.8lbs @ 54cm (Bike w/ Egg Beater pedals). The Ultegra Group is superb and carbon fork, seat post, & seat stay. The wheels are strong, I was 210lbs when I bought the bike and now 198lbs. The wheels are still true as when it was new. BTW these are Korso training wheels with 4mm blade spokes so they are tough. She is fast and stable. Fastest I've done so far going downhill is 48mph with no noticable unstability. For the price, you can't beat it. I'm actually enjoying Roadies more just because I can put on 25miles @ 16mph avg speed everyday right after work and not have to worry about going to the trail with my MTB. I just fell in love with the speed of roadies...