I've heard good things about their new ultrafina SE, but again, for heavy compound 3M uses a 3 step system, and with products like optimum, menzerna, and AI, you can finish in 2 steps.
I have very limited experience with the PI-3000 replacements for the PI-III RC 05933 and PI-III MG 05937. I did not like the PI-3000 stuff.
The RC didn't finish out nearly as nicely as the PI-III version or the even older-tech PI-II FCRC. Don't recall what I disliked about the new PI-3000 SMR (just got a sample from a shop that had some), maybe I just didn't like that it wasn't the same as the 05937, which I've always liked. So maybe I should be careful about casting aspersions on it if I can't say what I disliked about it!
Still, IMO the PI-III stuff was sorta special and those of us who really like(d) it probably won't consider the PI-3000 stuff to be a direct replacement. I'd go towards Hi-Temp or Optimum or Menzerna if you can't find the PI-III products or you want to try something else...those would appeal to me long before the PI-3000 line, but I haven't tried the PI-3000 polish for scratch-resistant clears either and it might be fine.
