“You mean those frames that are generally the lightest and most aero, with the most R&D behind them”
This. Giant made sixty frames during their design of the Propel. That’s not including all the CFD to optimize design, wind tunnel testing, rider testing…
R&D trumps a nice paint job. For steel, “ultimate” has other connotations for me. English, Cyfac, Pegoretti. None of these will have the performance of the best carbon, but they have other “ultimate” qualities such as elegance, pride of ownership, artisan craft.
So for me, a Giant Defy Advanced SL is my ultimate carbon bike. Not the prettiest bike, but one of the lightest, stiffest and most comfortable. I’ve raced it, sportived on it, ridden club rides, and got off after a 100 miles thinking I could do 100 more. And it hangs in the garage calling out “Ride me!” 😉