I've got a really nice carbon bike, a Look 585 with DA7900 and handbuilt wheels. I just did a 100 mile training ride on it last Saturday. However, my go-to bike is a 2012 (pre-Smartweld) Specialized Allez E5 frameset with DA7800. It gets the lion's share of my miles, and is my race bike for the coming year. It's fine for 100 mile days, and it handles better than the Look. Granted, most of that is because the Look is the endurance version of the 585, while the Allez uses the same geometry as the Tarmac, but there it is. For my purposes, the Allez is functionally better, and I wouldn't see an improvement in race results with a Tarmac.