Endurance road bikes generally sit too high in the front end. At a Specialized outing in Morgan Hill I had a butt puckering moment steaming down hill into a twisty section of road on an Sworks Roubaix. It was not designed for high speed cornering like we were doing. Jumped on an Sworks Tarmac and did the same course the next day and was just fine. The Roubaix was very ill mannered for me, the Tarmac was a saint.

I will need to ride a Synapse (road the first year production way back when, haven't looked at one since) and see how well it descends. I do see the front end is lower than Specialized, hopefully that shifts the weight forward.