Porter Cable 7424
You want to make sure it’s a true RO (random orbit) and not just a fancy right angle drill with a buffing pad. With a true RO, head moves around just like an orbital sander without spinning (when running free they may also spin but under any load they don’t spin). It should also have variable speed and don’t get carried away with the speed setting, slow and steady gives the best results (I don’t think I’ve ever gone above half speed). Having both 4” and 6” heads is also nice so you can have larger ones for open areas and smaller ones to get into curves and smaller areas. Being able to move the forward hand grip to either side or leave it off is also handy.
Gets lots and lots of different pads and buffers, they’re cheap compared to a new paint job. Some for wax on, some for wax off. Once you use a pad for applying stuff, never use it for any other purpose or product, even after cleaning. They aren’t that expensive and it will improve your results, different grits of pads, All pads should be micro fiber, especially for removeal. Lastly, replace the pads as soon as they show signs or wear for the best results.
I’ve had a Porter Cable 7424 with both 4” and 6” heads for about 10yrs along with more pads than I can count and am always getting more.