Depends on who you are playing against. Yoshi's Story is the worst map you can play on against a Marth, but possibly the best against Peach. In general tourney play, I do ban Yoshi's Story. However, I may not ban it if I know the opponent plays as Peach or Jiggs. As for the back air thing, you can double back air a lot of people and chances are, they are not coming back on any map. Very rarely will an enemy survive being hit by it twice off the stage and be capable of coming back.
Dreamland, I find that to be decent at best. Sure, you can live a while, but the map is so large that many enemies can live a while too(due to lack of really powerful knockback moves), which pretty much negates the advantage for the most part.
Battlefield is an excellent stage and very good for M2 overall. The size of it allows for pretty much everything M2 needs to fight effectively.(Tilts, nairs, ect...) Combine this with the fact that this is the stage to use the M2 glitch, and you have a pretty good setup.
I still always enjoy fighting on FD as well. Having no distractions and or changing environments makes dealing with just the opponent that much easier. However, I am sure this is how it is for the opponent as well.
Fountain of Dreams is my favorite stage simply due to the way it looks and the music. Has nothing to do with how well M2 plays there. I would say FoD is close to Battlefield in terms of how well M2 matches up. It isn't quite as good as Battlefield because the platforms change height and the M2 glitch here is not so useful.
