The first and only edition of Gamma World which I owned was the 3rd edition. Like a lot of games I bought back then, I never actually played it. I loved the concept of the setting and all the strange mutant creatures in it. You would have thought at the time that it was right up my alley. Alas, it was not to be. For one thing, the gaming group I was in was obsessed with DC Heroes because we were primarily a superhero based gaming group. The main reason I didn't like Gamma World 3e was because of this:
I was never a fan of the Action Control Table, especially after buying TSR's Marvel Super Heroes. I loved the idea of both games but didn't care for the game system that they used for these games. DC Heroes had a table based system to resolve actions but it seemed to be easier to work with. TSR's ACT system seemed to me to be more unwieldy for quick and fun gaming. The thing I appreciate about Mutant Future is that the rules system is far more accesible.