Kesler

2016 Cannondale SuperSix EVO Ultegra 4 with Ultegra derailleurs and brakes for $2499.
2015 Specialized Roubaix SL4 Comp with Ultegra derailleurs and 105 brakes for $2599 (was $2999 before sale price).
2014 Cannondale CAAD10 1 Dura-Ace C with Dura-Ace brakes and derailleurs for $2799 (price was $3499 before sale)
Also what are the main differences between the bikes in terms of frame etc

rms13

Carbon race geometry vs carbon endurance vs aluminum race

dksix

Are those the only 3 you're considering? I've seen some good deals on '15 CAAD 10 SRAM/disc. Out of my first bike budget but if I'm still riding a year from now I'll track one down.

Kesler

Ok so now its between the 2016 supersix and 2015 roubaix. The Supersix has Ultegra brakes and the roubaix has 105 brakes. Derailleurs, cassette, and chains are the same. Is it mostly a choice between comfort and speed?

ColaJacket

Endurance Geometry vs. Race Geometry is a pretty big difference. They're both carbon bikes with a mostly Ultegra groupset. So they're pretty similar.

The big difference between them is going to be how they ride. Only YOU can determine which one feels best when YOU are riding it. Ask the LBSs if you can take them out for a 10-20 mile road test. If need be, see if they have a group ride of that distance, and see if you can take each bike out that way.

Make sure the tires have an equitable pressure in them for your size, and if you have a saddle that you already like, use that saddle when you do the road test. (Same with pedals/shoes.)

When you finish road testing the 2 bikes, come back and tell us your impressions of the rides.

GH