why specialized? there are plenty of good manufacturers out there

but for comfort, roubaix is the one. it's got a more upright geometry, and designed for rides that are long and/or bumpy.

but comfort is relative. I happen to find my aluminum caad to be comfortable enough.. with 25mm tires, unless I'm doing cobbles or gravel, it's all the same to me. but that's personal

there are plenty of people who also prefer a more aggressive geometry. it's up to the individual. I would recommend getting a used bike first, or figure out what type of rider you are