MK vs DC is perhaps the most purely enjoyable fighter I've played in years and it's without a doubt the best MK I've played since MK2.
Understand this first - there's no excessive blood or gore or gruesome fatalities- And guess what? It doesn't matter. At all. The story mode in this game is unlike any other in the history of fighting games. (At least that I can recall)
For one thing, it's exceedingly well put together. It's well written and is chock full of fan service for any DC comics fan. It's the little touches, like the great character interactions, that are so very much appreciated. Most of this stuff is almost unheard of in a fighting game. This is a cohesive narrative that is pure comic book goodness. The DC ending alone will make you squeal with nerdy glee.
Technically, the game does have its flaws. Marvel vs Capcom this ain't. The combat, while not bad in any way, doesn't have the overall depth or flow of Capcom fighters. But if you like MK, you already knew that and you probably don't care. The graphics are terrific though, stages are vivid and well detailed and the characters themselves are very well done AND well animated. Some of the DC costumes have slight re-designs. Don't get all fanboy now; it's actually good and they all look really cool.
This is good stuff all around. Even if you're not the biggest fighting fan in the world- if you like classic DC characters, this will make you smile. Lex Luthor alone is worth the price of admission.
Bring on the sequel!