SaiKaiTai, I tried the same bike, the Giant OCR C. I tried a 0 and a 3. The 0 was set up with Ultegra triple and the 3 with 105 triple. I took three rides on these bikes and had put the 0 on hold last August when the doctor took me off of the bikes due to a problem with my left hand. I removed the hold and the bike sold. Your comments about the bike being so smooth, almost gliding and seeming to pedal itself are the exact feelings I had. I was OK with the cassette as Giant set it up, but that's an individual thing. I envy your position because I'm off of bikes following some shoulder surgery. I wanted to post here to encourage you that your feelings about the Giant OCR C are similiar to mine and the owners I interviewed when I thought I was about to purchase one. I'm confident I will be cleared to ride bikes in less than four months. If that happens I will probably purchase a Giant OCR C. Good luck with your decision.