regarding ride quality...I don't know if it's the difference in steel type, quality of build, different size and geometry, but my slightly-too-big-for-me '89 55cm paramount (columbus sl?) rides way more smooth and solid feeling, than my mid-80s 53 cm bottecchia (columbus aelle) that supposedly fits me. (I'm 5'8")
edit: after riding ~30 miles on the bott, and likewise on the schwinn a few days later, I reckoned the bott 30 would equal about 50 or 60 schwinn miles as far as body fatique and overall workout "feel" afterwards.