I use Meguiar's M100, M86, and M205 more than anything else.
If I can stay away from diminishing abrasives I will. My mind never thinks I've broken down the abrasives enough, and I'm left with this uncertain tension after polishing. With a non diminishing abrasive I might be able to do one pass, wipe off, and be done. Significant time saving, and easy wipe off (most times).
I use all the Rupes gels with their tools when I use them. They are all very good. Keramik (fine cut) is excellent, as is UHS (compound/polish). Zephir (coarse/heavy cut) can be temperamental and dusty. Quarz (medium cut) can get dusty. Diamond (ultra fine) can be a pain to wipe off. Overall they perform exceptionally well, I'm just nitpicking.
I have some Menzerna.
I have 3D/HD Cut +, One, Polish +, Speed, and Poxy coming on Saturday. I have high hopes for these guys.
As far as M205, it can be your best friend, or worst enemy. If you're in a situation where it won't finish out it will be wildly frustrating. If you strike gold, and it only takes one pass, you will want to place the bottle on the nightstand for safe keeping.
Very rarely have I had it not finish out.
I also love the Ultimate line.