I've owned, raced, test-ridden a few bikes and even had a custom frame built for me, but this 63cm F55 is the most comfortable bike I've ever owned.
Before getting this bike, any ride over 60 miles always involved at least a little discomfort; but I can ride just about all day in the drops if I want to.
I don't know if they are necessarily a superior bike or if I finally got lucky with the fit on this one, but mine's the dog's-bollocks and the cat's pyjamas. The only thing I'd change about it is the flat-black (asphalt camouflage) paint.
-CCinC