I can comment on the Synapse but not on the Roubaix. I bought a new '08 Synapse Carbon 5 in the first quarter of '09 and got a discount on it as a last-year's model. Longest ride so far is 90 miles, but it did well. Have done an 80, and some 70's and 60's as well. No problems. Mine has all Shimano 105 components. So far, I have 4,200 miles on it. It climbs well and descends well. Max speed so far is 48.5 on a descent with no shimmy. The original saddle was a little narrow for me, and I have switched to a Specialized Avatar, which I like. This was my first venture into carbon, and I am pleased with it. My old bike, which I still ride, is an aluminum Fuji Newest. I prefer the ride on carbon. Wheels on the Synapse are Mavic Aksiums, and they seem to be holding up well. Good luck with your search.