ShinyChevy said:
Please tell us more about the differences - which light polishes do and don't work on which clear coats?
I'll do my best... Keep in mind that I try to split light polishes into two categories: "Light" polishes and "finishing" polishes. To me, a finishing polish is one that is just barely functionally abrasive. One that is meant to do nothing more than remove the very lightest holograms and increase the gloss. Light polishes are one step above that, capable of removing some light swirling.
Some light polishes manage to finish down so well that they go cross-category and fit in the finishing category, as well.
Light polishes:
PO106FF: Very good on hard clear coats. On very soft clear coats, it can hop, jump, stick, and give yucky results. This isn't consistent; sometimes it'll work well on soft clears, sometimes it won't. 106 can be a very fussy polish sometimes, but when it works, it's easy to use, has good bite and finishes down well. Same with it's cousin PO106FA.
Optimum Polish: very good on medium and softer clears. About worthless on hard clears. OK defect removal, finishes down decently. Way too long of a working time.
1Z Hoch Glanz: Fast and easy, but *only* on hard clears. Will trash soft clears. Leaves nasty *compounding* type haze on soft clears. Has about as much correcting ability as 106FF. Works well with a PC.
3M Ultrafina: One of my favs. Works OK on hard clears, but will more than likely require two applications. Works fantastic on medium and soft clears. One of the only polishes capable of finishing out holo free with a rotary on Bentley-soft clear. Fairly decent defect removal ability, and finishes down darn near as well as a dedicated finishing polish. Very fast. Four passes and you're done. Extremely easy to use. This stuff is "Bubba Proof".
Menzerna Final Polish: Reminds me of Optimum Polish. Similar characteristics. Gotta work it a long time.
M205: With a PC, this stuff rocks. Very good correction, even on hard clears (just work it a bit longer). Finishes down to an amazing gloss *on hard clears*. On soft clears with a PC, it'll finish down well, too. But with a rotary, I can only get it to finish down well on hard clears. Very good correction ability. Some of the best I've seen in a "light" polish.
"Finishing" Polishes:
Menz PO85RD: IMO, this is the finest finishing polish on the market for use on hard clears. It can be used on softer clears sometimes, too, just don't be shocked if it doesn't perform well on soft stuff. Insanely long working time. Easy to use as long as you're using it on hard clears. Has almost zero correcting power. It'll get out light holograms, but don't expect it to do much swirl removal, unless you're working medium or soft clear.
Menz Final Polish II, aka Micro Polish: IMO, this is the very finest finishing polish on the market for use on soft clears. Very easy to use. Has no game when it comes to correction. It's just barely able to get out holograms. Another absurdly long working time polish. Work it a *long* time to get best gloss out of it. Multiple applications are required to really get the best out of it. Will finish down holo free with a rotary on even the very softest clear. Plan on packing a lunch if you really want to get the best out of FPII; you'll need multiple applications, and you'll need to work each application a long time.
Polishes that cross-over to finishing: PO106FF, PO106FA, UF, M205
Edit: Of course, this isn't meant to be a comprehensive review of all polishes out there. Just my quick opinion on some popular products. YMMV, etc.