Quote Originally Posted by aicabsolut View Post

Keep in mind that the Cannondale geometry will be pretty different from the Roubaix. Generally, I think people go down a size in Cannondale, but that's not written in stone or anything. It may mean you'd want a different stem or something though than with the other bike.
Absolutely! Fuji measures center to top to get the frame size, while Canny measures center to center (at least they did the last time I owned one). Bike sizes are just like clothing sizes- what fits in one brand won't necessarily fit in another brand. Stick with the actual frame measurements to compare, rather than sizes, and you'll be fine. It sounds like your shop is really taking this into account, and won't assume that you need the same size in both bikes.