I use a 0-1750 rpm variable speed polisher, you can still burn paint with it so you have to keep it moving constantly like anything. I have a single speed 2450 rpm polisher but it is a bear, better as a sander IMO. I use the Meguiar's in the brown bottles too, you can start as aggressive as you want and work you way up to the final polish, takes out a lot of the guesswork. I have had good luck bringing back scratched and orange-peeled clear coats with it (and a lot of wet sanding), the paint is so deep it looks like you could dive in when you're done.
I like the Meguiar's because it is paintable, so no refinishing problems with the old paint. I always wonder if those miracle paint restorers could have silicones or some other chemicals in them that could cause bodywork/finishing trouble down the road?
Allan