Mostly price. The best price I found for the FSA was $42 + shipping. I got the Ultregra from Nashbar for Just over $20 due to coupon. I was also already ordering a chain (also Ultregra) and other stuff from Nashbar. Most of my components on the bike are Ultregra and I tend to try to keep the same level of components when possible. I searched thru several posts on the FSA cranks and some folks on here felt FSA is not that great. Don't know if Ultrega is any better. Nashbar did not carry that specific cartridge and I try to use the same vendors I have used in the past and had good results with.