Here is what I use to detail my cars:
1. Porter Cable 7424 random orbit polisher, very safe and effective for paint that is in good shape. Use it for minor defect removal, polishing for gloss, and final wax/sealant.
2. Now this one is for the serious detailer/diy person, a Porter Cable 7428 rotary buffer. This is equipment used by body shops and it is capable of doing tremendous damage in the hands of an inexperienced person. Tool is used to remove much more severe paint damage, including deep swirl marks, scratches, and water marks.
For minor swirls, PC7424 with a light cutting foam pad and 3M Swirl mark remover is sufficient. Deeper swirls and scratches (ones that could be felt with your finger nails) require a PC7428 rotary with a cutting pad and 3M Fine Cut compound. Please bear in mind that DEFECT REMOVAL MEANS CLEARCOAT/PAINT REMOVAL and it takes a lot of experience to do this properly. The combination of foam pads and compounds are almost endless to achieve this but it requires know-how and experience.
For regular polishing and waxing, a PC7424 is your best friend. It is fool-proof and very very safe to use due to the random orbit action minimizing heat generation. My personal choice for paint protection is Klasse, easy on/off with long lasting acrylic protection. The bottom line to achieving the ultimate shine is all about surface preparation and having the right tools. Note: Products mentioned above are my personal preference only, many equivalents are available.