What's really weird with the combo system is the buffering. I can't buffer things for shit when I play this game. The window is absurdly small (maybe because I'm so used to DOA) and for most juggles, you'd have to wait for like a quarter of a second before inputting your next command.
I do regret buying Injustice because I only played it for like 4 hours including Story Mode before leaving it to collect dust on my shelf (and it was the bonus edition with the zombie DLC code, dammit). I don't really find the model details particularly good-looking and the story, while relatively better than most fighting games, is still underwhelming. I'm not a DC fan, so maybe that contributed to why I didn't find it that interesting.
But one thing this game does so well is stage transitions. They put DOA's multi-tiered stages (even DOA2U's) to shame.