Is there much difference gameplay-wise between BB and GG? They're made by the same company, but I get a vibe that people prefer GG a little more. Personally, I found Blazblue to have much more appealing characters, but I don't really know much about GG... Apparently both Blazblue and GG are getting new releases (this year?) too, though I think GG's is a bit farther in the works than BB's, since there's no release date for a console version of Central Fiction yet. If I were to try GG, I'd probably wait until Revelator comes out so as to have the newest version.
I've actually already played a bit of MKX at a friend's place. I grew up on MK, but left it for Tekken because of the combo system. However, I did find MKX to be really fun, moreso any other MK game so far. I'm just a bit concerned that it doesn't have the depth for something I'd want to play with a competitive mindset. I've heard you tend to see the same few characters doing the same combo over and over.
UMvC3's combo system is simultaneously my favorite and least favorite part of it. I actually already own the game, but I've only ever really played it casually. I like how deep the combo system is, but as you said, it favors certain characters objectively over the rest. Thankfully, some of my favorite characters are those top tier characters, such as Vergil and Morrigan, but my other issue with the game is execution. Long combos including flight cancels and whatnot are so complicated and demanding to do that it almost takes the fun out of it for me. I'm sure if I really dedicated myself to it I could learn them (I've already managed some shorter versions in practice), but I'm worried I'll end up hating playing the game along the way. Maybe the end result is worth it though.
I've actually seen a few of his videos already. He seems like a pretty insightful guy and has a lot of good stuff to say about fighting games in general.
It seems like Street Fighter is of course a popular pick as well. I might just end up getting SFV alongside another one of these games, possibly Blazblue. I've been out of the loop on Street Fighter since SF2, so it's been a while, and I've been meaning to get back into it at some point anyway. Anyway, thanks to those who responded! I have a much better idea where things are at now, though I'm still not 100% decided on what I'll choose.