One of the big differences is rotary vs dual action vs random orbital. Rotary is like a drill, it just spins. These are more aggressive and create more heat faster. Dual action oscillates differently and so does random orbit, check this link for diagrams
https://itsbetterwaxed.com/blogs/det...and%20rotation.

Rotary are usually the cheapest, but I've heard dual action is easier to control and harder to screw up (ie, burn through the finish, or create swirl marks) I've only used rotary for a few armature jobs but I want to get a dual action. The cheapest dual action that seems decent is the torqx that comes in a chemical guys kit at Canadian tire. It goes on sale sometimes for under $200. It says dual action and random orbital both on the same page so I'm not sure what it actually is!!

https://www.canadiantire.ca/en/pdp/c...q=polisher#srp