Analyze what your needs are and you'll find which tool you'll need. For a GOOD rotary (Milwaukee, Dewalt or Makita perhaps) you're looking at 200 bucks, and for the Random orbital you're looking at a PC for around 100. Throw in another 50 bucks for backing plates and pads and you're set. In the long run, this 100 dollar difference is NOTHING.
If you're looking to do just light polishing on cars 2-3 times a year, the PC is for you.
If you're looking to remove serious defects then you WILL need a rotary. It will also cut your light polishing times considerably.
There IS a learning curve to the rotary, but it isn't long if you have confidence in yourself and your abilities.
I started with the Porter Cable 7336 DA polisher from Lowe's. Then I had my car repainted, and decided I needed to WETSAND. The PC wasn't going to TOUCH those sanding marks, but the rotary could. So I bought a Dewalt 849. I practiced on two hoods and felt ready to go. I coulda used more practice, but the window of opportunity to wetsand was open so I took it...
Everybody's needs are different. Find what you're looking for and get the tool you need. Or be like me and get both!!!