So I got the chance to play this at Best Buy today, both versions.
3DS version, I picked MERGERMERN because why not. Chose the Reset Bomb Forest stage to check it out. His moveset threw me off at first since I'm used to A being more physical attacks like punching and kicking and B being for specials, but his are spread amongst the two. For instance, Down+B is Leaf Shield while Down+A (in the air) is Hard Knuckle. Anyways, it was fun and I pulled off his Final Smash twice. It looks beautiful in 3D and Black Hole Bomb has a lot of reach. Also, after the Reset Bomb hits the stage (around a minute into the match) the field changes completely and almost all platforms are destructible, so it's quite chaotic as your foothold may not last for long. I only got to play one match (and one match on Wii U) but what I did play was beautiful.
As for the Wii U version, I chose Kirby and forced everyone else to let me pick Wily Castle to see Yellow Devil. The stage is basic, of course, but once Yellow Devil shows up it makes sense. Whereas in other stages the assorted platforms and stuff can trip you up, it's Yellow Devil who messes you up on this stage. He's incredibly damaging, especially when he's moving across the stage like he always does (I think it's the same pattern each time, which is also the pattern in MM1 so props for that attention to detail). It's very hard to dodge him. Anyways, Kirby plays the same as always. I wasn't able to get a Final Smash to check out dat Ultra Sword, but I did manage to eat someone who was playing as Little Mac. And Kirby gets Mac's hair and eyebrows (which is funny cause Mac's hair almost looks like a pompadour when on Kirby's body). It was super adorably fabulous.
Oh and someone got Midna as the Assist Trophy and she is supertough. Easily threw me out of the opposite corner of the stage from where she was.
Anyways, though I didn't get much playtime (especially after waiting in line for four hours) what I did play made me sure that these are gonna be as top-notch as ever. And they also felt like a nice mix between Melee and Brawl.
Oh and one of Mega Man's color options is the ol' red and grey. If only he had a scarf too...