I wanted one of those and was about to order one a few months ago.
"Dremel" is just the brand name of that company that kinda made it popular, the rest are called rotary tools and they all accept the same size bits. You can buy "Dremel" bits and stuff and use them on rotary tools.
They have a few different types, Dremel, Black&Decker, & some other lesser quality ones. Each brand had a few different versions. Some had a single ~18krpm speed, others variable from 8krpm up to 36krpm. I HIGHLY recommend getting a variable speed one as being too fast will melt certain materials and sometimes you want fast or slow. Some came with package deals with accessories bits and stuff.
There was a Dremel one that was like $60 that came with like 50 accessories (just discs and pads and stuff) and a little case for just the Dremel and those parts, nothing else, it was variable speed from like 8k-36k. Was going to get that till I saw this one...
It is a Black & Decker one, cost $60 as well but came with a much larger case, although plastic it's like 1x1x1.5 foot and will hold all your rotary tools you buy in the future and other things you would use with it. It's 8k-30krpm (doesn't go quite as fast as the Dremel but no need really as the B&D has more torque anyways), also came with 100 accessories, again, just a bunch of discs and pads and stuff but still a good starting point.
Works really good and I wish I had this LOONNNG ago. I've polished lots of things with it, can sand things, cut holes for speakers and holes in walls when I needed to fix a crack, ground down some sharp edges on a pipe that I used to replace the resonator in my intake... it's just REALLY handy, lol. Especially cause of it's small size making it easy to manuever, it's powerful even at that though.