I am 6'4" and 245 mid forties. Test drove both of those bikes and much preferred the Roubaix - even the Tarmac has a pretty good riding position these days. If you can try out a Cervelo RS or R3 they are in price range and well loved by many.
I got an Argon 18 that is not as comfortable as Roubaix but the price was very right. I wanted a frameset and Specialized Canada were robbers - way worse pricing and sizing than US.