Buffers are dangerous. You can just as easily destroy paint as enhance it.
This statement is a bit misleading. Not all "buffers" are dangerous because they aren't all the same.
There are three basic paint polishing machines on the market:
(1) Orbital Buffer - These are the buffers you find at auto parts stores, Sears, Home Depot, etc. Cost is usually around $50. They operate in an orbital motion and use a terrycloth bonnet to buff on wax. Their motors are low torque and operate at one speed. These machines are fine for applying cleaner wax or maybe a light polish. Operation is literally foolproof; a kid can use one of these things. If you want a basic, cheap machine to buff on some NuFinish or Turtle Wax, an orbital buffer is OK.
(2) Dual Action Polisher - These machines are for more serious car nuts and detailers. They are derived from orbital sanders used in woodworking. While they operate in an orbital motion like the buffers described above, they have high torque motors and adjustable speeds. The advantages of a dual action polisher is you can use them with a wide variety of foam polishing pads and polishes to get top notch results. The overwhelming choice in dual action polishers is the Porter Cable 7424 and its variants. A basic polisher will run you $100-150 but you'll need pads and polishes, so your initial investment is more like $200. A dual action polisher can do almost anything a typical car owner could want.
(3) Rotary (Circular) Polisher - These are the high speed polishers you see used by pro detailers and body shops. A rotary polishers used with a foam or wool pad, the right polish, and an experienced operator can get spectacular results from any paint job. Their high speeds generate enough heat to remove serious oxidation, scratches, scuffs, almost any paint defect. If a rotary cannot fix the problem, the car needs to go to a body shop. The downside to these machines is the potential paint damage if used incorrectly. The speeds generated can easily burn paint edges and create serious buffer marks. It's easy to butcher your paint job with one of these, but used properly, they can work wonders. Top brands are DeWalt, Porter Cable, Milwaukee, Makita and Hitachi. Costs are $150-200 for the machine, add for pads and polishes.
I hope this overview helps y'all understand what machines can and cannot do. Let me know if you have any questions.