I bought the Trek 7700FX last year. I only test rode the Trek 7500 and 7700, as I knew I wanted a high end hybrid and the did not have any of the Cannondales. (The Trek Cyclocross bikes were out of my price range.) There is quite a bit of difference between the two Treks. The 7500 is built a bit more like a MTB, the gearing and frame angles seemed to me a lot like my old Trek 7000 MTB. I don't know a lot about components, but I think the 7700 has a lot better components as well, and the geometry is a bit more like a touring bike. It only took a short ride on each for me to tell which one I wanted, so I recommend you do the same. I've been so happy with mine that my husband is thinking of buying the 2003 7700FX, and it looks pretty slick. The Cane Creek bar ends are awesome, and this year the 7700 (at least the one we looked at) had Shimano clipless pedals. (That's my next purchase if anyone has any recommendations.) Good luck! Shana Germantown, WI Training for my 1st Century!