I just go a PC 7424 and I am happy with it. There is also a model called the Ultimate Detailing Machine UDM with a little more power but it has been having alot of problems and many are not that reliable. There are faster intermediate models that spin and orbit between a random orbital and rotary that offer faster speeds, more correcting ability while being safer then rotaries like the Flex and Mikata models but they are expensive, cost more then a orbital or rotary and are not nearly as common of the PC and pads and backing plates can be hard to find/expensive. With the right pads and polishes the PC is a very versatile machine and can take car of most painst issues swirl marks, light sanding marks, light scratches, oxidation, etc while still being safe and affordable.