Rented the game yesterday and fiddled around with it today for a couple hours too.
Super impressed with the offline content, presentation, and the amount of things to get lost in. This game is anything but bare bones like MvC3.
I played one match online just to see how the online was set up. The options there are fantastic and my one match was silky smooth, but I ended up getting bodied pretty hard.
So far my favorite character was Smoke. He's fast, fairly safe, great mix ups, great health, great damage, and just all around bad ass. I don't like his main outfit though so if anyone finds his alternate in the krypt let me know where it is so I can go unlock it.
Sonya was also impressing me. Dive kicks, great punishes for projectile spam, air throws, etc. She seems like a top tier character in my book as well as Smoke.
Oh and before I forget, the story mode is fanfuckingtanstic. It's not AAA story line of the year, but after having played so many fighting game story modes that were don't be a drunk monkey it's refreshing to see a well laid out plot to lose hours into.
Well done NetherRealm. Looks like losing Midway was just the kick you needed to get back in the game.