Shuma-Gorath
I have to admit that I'm a big fan of Shuma-Gorath. In the earlier games, I always thought he was the weirdest addition to the cast. He's

not terribly popular in comparison to other villains, and he was an extremely powerful entity that would seem difficult to translate into a fighting game. Well! As it turns out, if you completely ignore his comic book canonical strength, he adapts pretty well as a shapeshifting fighter! I loved using him in Marvel Super Heroes and all games following. There's just something euphoric about beating people with a cycloptic tentacle monster instead of using a classic superhero or street fighter. I was very pleased with the fact that he kept being brought back in all subsequent games. To me, he's as much of a staple to the series as Ryu or Cyclops (Pff, oh wait, sorry Cyclops!).
So, I'm glad he found his way into MvC3, and I'm glad he's still so fun to use. Initially, I was worried about his special moves being predominantly charge inputs. I mean, of the existing roster, only one character has a charge input, and that's just one move(Hulk). It's not like charge characters are particularly hard to use, but I've personally always had trouble getting their moves out in a timely manner. As you can imagine, for a fast paced game like MvC3, that could prove disastrous. Luckily, you can charge while doing your combos, so it ended up being not that big of a deal of all.
Shuma joins the ranks of the type of character who loves smacking you about in the air, with some of his best combos taking advantage of that. Aside from his main launcher attack, he's also got a mini launcher in the form of crouching C,

Jill
Initially, I was excited about Jill's return. Who doesn't love hearing about how she's a member of S.T.A.R.S.? Unfortunately, that excitement

It was a good thing I was trying out Jill expecting to be disappointed. I was pleasantly surprised. She doesn't bring anything terribly new to the table, actually feeling like a recycled mish mash of

several existing characters (Wolverine, Wesker, and X-23 come to mind), but she does play differently enough to feel unique. She's fast, has an OTG grab, a dash akin to She-Hulk (or a version 0.5 Wesker teleport), a grab that flips her position ala Yun from SF, a dive kick (er, knees), and a level 3 hyper that is like Wolverine's Berserk, except on crack. Using it with level 3 X-Factor is practically unwieldy! She's definitely funner to use than I expected, though I can't say she will have any permanency on my team. Her appeal is low when compared to fighters like her. Maybe I'll reconsider when there comes that inevitable costume pack that contains Jill in her classic RE1 outfit. Or the one from RE3...