what are the main differences, other than the hats, between that posted above and this
It's exactly the same set. There are two different types of packaging, one with the hats on, and one without, but they both have the hats included (which are removable).
Saw it. Liked it. Not for $50.
If you're into the Mattel line, these are a great deal, considering they charge $20 a piece for single figures as it is, and they've never released any GBII figures at all until now. Separately, they'd be $80 if they sold that way. If you really do like them, you're not gonna find them cheaper, that's for sure.