I don't have much experience with those except for the fact that when I was starting to look for a bike, at one of the shops I rode a CAAD9 6 and a Scott Speedster. Both were the same size, but the Cannondale felt really cramped and maybe a bit more aggressive than what I was looking for. I think the Defy is meant to have a more relaxed geometry. With that being said, I bought a fitness/hybrid bike, but now I'm planning to get a road bike. The TCR Alliance 1 and Defy 1 are on my list of bikes to try and look into, so I'm interested in this as well.