Re Pace, I dunno what the new stuff is like but with the old aluminium square tube frames it definitely seems to be a case of when, not if, it cracks yet you still see them changing hands at silly money. Like I know there’s less of them left in one piece so there’s scarcity but at some point you’ve gotta just be like yeah, there’s none left coz they’re a bit shit!
I’d add:
SDG I beam seats/posts. I had a regular railed Bel Air and loved it, rode my mates bike with the I beam version and it was horrible. Turns out rail flex is a good thing!
Thomson 27.2 Dropper. I bought one as a bit of retail therapy when a job didn’t go my way. It’d have meant a pay cut so staying where I was I treated myself to what was then a £400 seatpost and it was awful! In the year I owned it it was back at the distro for warranty repair 3 times. Had to be sent special delivery every time because of the value, never took less than a month to repair and get back to me. When the cartridge started to go I just cut my losses and got rid. Have always gone for the dirt cheap KS/Brand X Droppers since and they have all outperformed the Thomson by a large margin.
Gates Belt Drive. In use, brilliant. Where I thought it fell short was trying to live with it. You want to change gear ratio? £££. You want to fit it to a different type of hub? £££. You want to use different cranks, chainline has to be spot on. You want to fit it to a different bike? Got to worry about a stay splitter, got to worry about chainstay length, got to worry about chainring/pulley clearance.