Sonic: Love playing as this guy. Not only are his attacks fast, but they actually pack a decent punch now. His homing attack got a big buff, so you can travel REEEEALLY far with it, and the move itself is kind of hard to punish after shielding it from what I can tell. Spin Dashing is a mix. Even though it does some pretty good damage and can actually combo into Homing Attack, the constant spinning noise is just ear raping. Other than that, he's improved a good deal during the transition from Brawl.
Meta Knight: Oh, how the mighty hath fallen. Both his side and neutral B's have lost the ability to grab the ledge, thus greatly limiting his recovery options. Along with that, neutral's lost a lot of duration time, and side's lost its draw-in effect, so you can blow by your opponent after hitting them and barely do any damage, and it also lost the little jump thing it does when it ends in the air, making it a pretty terrible move. On the bright side though, Galacta Knight costume!
Bowser Jr.: Gotta say, it's pretty fun playing as him. He has a lot to offer, like a god damn cannon, a throwable bomb, and he isn't completely helpless after using his recovery. His side special is also pretty neat for approaching. His Side Smash is really satisfying to land, whether it kills or not, though his other Smash attacks leave a bit to be desired in my opinion. Also, his tilts and pummel are adorable.
Lucina: At first I thought I'd hate her, since she doesn't have the tipper effect like Marth does. But then I started playing as her, and sure enough, I can't find myself using Marth over her now. She's like an easy mode version of Marth; you don't get super powerful attacks for tipping, but your power is nice and consistent no matter what. Besides, she still has her spike, so no complaints here. She probably won't be super good in tournament level play, but it's good to not rely on tippers to KO.
Charizard: It's one big step forward, one little step back with this one. A lot of his attacks are much faster, he has a lovely F-Air now compared to Brawl's, and Flare Blitz is both a decent recovery option and a nasty move to get hit with. Sadly, his D-Air seems to have received reduced range, as well as a sourspot if you don't hit with the foot. It's a shame, since that was my favorite move to hit people with.
Yoshi: I'm actually quite surprised by how much Yoshi's improved. His second jump doesn't have any delay when rising, his B-Air is pretty powerful, his Up Smash is a little faster, his Egg Roll is smoother and more reliable to use, and his Dash Attack has become better overall. Some of his moves got faster, and I've found that you can jab and then combo into a tilt or Up Smash, so his combo game got a little better. An enjoyable new spin on an old relic.
Samus: