A brand-new, never used, fresh-from-the box simplex prestige shifts wonderfully. Unfortunately, the plastic ages very fast and as it ages, flexibility increases, so that after just a few months the shifting is horrible - you have to overshift for every gear, then return. The levers, as the plastic oils leached away, got brittle and tended to snap off, making a new gear system a necessity.
All present Simplex Prestige derailleurs, even the "NOS" ones, now have aged delrin plastic and will not shift as well as when they were fresh from the box in 1972. The Simplex Prestige shifted like a banana. Nice and firm for the first few weeks, then it turns brown and gets mushy.
I threw away my Prestige and bought a suntour VGT, and for the levers I got campy shifters. This was absolutely beyond a doubt the best shifting combination of all time, hands down no holds barred, and I can say this with authority because I'm certain that nobody else has ever tried it and therefore nobody else can protest. :-) :-) :-)
- Don Gillies
San Diego, CA