I have owned, built and ridden hundreds of vintage road bicycles, and compared each one to the others, on purpose. Been doing it for years.

Personally, I can't tell the difference between most steel frame sets. Aluminium offers a much stiffer ride than steel and that I do notice. I have never ridden a carbon fibre bike so no offering of opinion there. So, what is the difference in feel..?

Nothing, as nearly as I can tell. Feel, to me, is all about frame construction, geometry and intention for use, in my opinion. Take the stiffness of aluminium that I noticed. My Vitus 979 was all alloy but anything but stiff. And that was a design issue, not a material issue.

So, in my opinion, what kind of steel tubing it is is irrelevant, unless weight reduction is the primary focus.

Again, this is all opinion and based on my personal experience. My present favorite rides are a 1977 Motobecane Grand Jubilee with Vitus tubing and either my Cyclops (Columbus SL) or my Wateford (Reynolds 753 frame and 531 fork). I should add that I have not had time to give the Waterford a decent chance to show its virtues. Which is best...

My guess is the Cyclops will win the contest for best ride quality but not because of tubing used. The Waterford is an aggressive geometry racing bike and not necessarily designed to impart rider comfort. The Cyclops sports less aggressive geometry.