I have a 2009 Synapse 5. I to was looking at the Trek 2.1 & 2.3, and the CAAD 9. I started out wanting the CAAD 9 because of all the hype but there was just something about the Synapse I liked a little better. FWIW I found that I needed one size bigger in the Trek over the Cannondale. So in my case a 56 Cannondale compared to a 58 Trek. If you want a performance bike that is oriented to a more comfortable ride for long distances then the Synapse is your bike. When I decided against the CAAD 9 it was because I realized I never intended to crit race (or do any racing for that matter) and just wanted a performance type bike I could do long charity rides on, etc. I am glad I picked the Synapse and never looking back.