Stock GPU Fan Type Differences

I've always wondered, with the multiple manufacturers for GPU types, there seems to be two types, the ones with 2-3 fans and the other with one spinning radiator thing.

What is the difference? I'd assume the fanned ones are more efficient, but if the spinning radiator fan is still a common alternative then it should have some merit behind it.

I'm planning on building a small micro-ATX based computer and wondering which would best suit it. Any recommendations?

Thanks Guys

Hey look guess what google found!

So they're called blowers...
i kept looking up radiators because i had no idea what they were.

Watch the vid and it makes so much more sense now how they work.

Thanks guys!