Alright, so, I've had time today to play Smash 3DS for about 2 hours now today, initial impressions:
-Playing on 3DS is... odd. Not as bad as you'd think, but weird- dash-dancing is very difficult to do and probably not worth it, for example. Especially after playing Melee and Brawl with a Gamecube controller for years. I'm getting the hang of it though.
-The game looks better in 2D than it does in 3D. Still, I haven't seen a 3DS game run that well in 3D since A Link Between Worlds, but the visual quality is noticably better if ya just leave it off.
-The game feels much more like Brawl than Melee. It's certainly a lot snappier though, it has its own feel overall but it's certainly closer to Brawl.
-The new characters all feel great. Can't pick a favorite! And the veterans all feel better from the one's I've played, the playing field will certainly be more even this time around.
So, yeah, it's definitely a great Smash Bros. game. I think it'll take some getting used to for everyone to enjoy though.