Menzerna will beat any 3M polish easy.
3M has the biggest marketing divisions known in car-care re-finishing and repair. Some are not bad at all, others are so so. All depends on what application you are looking at.
Menzerna is known to have the worlds best abrasives and is an OEM/Tier1 supplier to MB, and other mfg in the USA.
Again, all depends on application. Menzerna wins in the OEM market. Aftermarket is where they lack in marketing. Besides, the majority of thier products are for OEM and not much on the detail side. They do have a detail line, but not widely known. Most of us still use the polishes used in repair/refinish work. Those are:
Powergloss
Intensive Polish
Final Polish
Micro Polish
Glaze
And several others used for hard clearecoats: Ceramiclear etc, but are used on the OEM level when the finish is still curing/warm.
Depending on what your needs are, and your level of expertise, I'd try some of the Menzerna polishes and see how you like them. BTW, they ARE designed to be used by a rotary, but can be used by PC with a little know-how.
3M PIII FG contains a caranuba if you are un-aware. The PIII-MG does not.
Regards,
Deanski