I am switching from an OCR 1 to a Specialized Roubaix (base road model). The OCR 1
was a great bike, but the "large" never fit me quite well. My new Roubaix is a 62 cm. frame, perfectly tuned in for a custom fit. Even though it was not a good fit, I did love the ride of the OCR 1. Smooth, easy handling, and the 105 group was perfect.
I do not think that I'm an advanced enough rider to appreciate Dura-Ace or Ultegra.
Bottom line....MAKE SURE YOU ARE PROPERLY FITTED !! It makes a world of difference. A good LBS should be able to properly advise you on the fit. The Specialized bikes, in general, have a wider size range. TEST RIDE THEM BOTH !!