Frank Berto is fond of saying that they should have named the Prestige the "No Prestige".

My experience reflects many of yours. The Prestige rear derailleur, out of the box, was probably the best performing of the boom era, European derailleurs. But they wore quickly and things got sloppy. I never liked the front derailleur. I also subscribe to the shifters being the weakest link. Very high effort was required to shift onto a cog of more than a couple teeth differential, due to the flex and high friction plate pressure that was required. Switching to metal shifters, Hyperglide cogs and teflon lined housing is a revelation in performance.

I always wondered how the early 1960s Prestige models without any metal reinforcement in the derailleurs or shifters performed? The single pulley Cadet must have been horrific.

As you proceeded up the line, you got lass Delrin and better performance and reliability. An SLJ model with retro-friction levers offered superb performance for the era.