My favorite stage by far to fight in is probably battlefield since it's the most Neutral one while still giving some advantages to some fighters. Otherwise, I really love Gaur Plains, and the zelda stages but that's mainly by the music they contain.
Ban pacman stage on SSB for wii u.
My least favorite to play on has to be the Donkey Kong stage, even though I LOVE that it exists. It just doesn't really work well since its so many tiny platforms.
Then one where you're sent like far behind the main stage? That one is really really weird