I know it's not Broadway, but School Girls; or, The African Mean Girls Play is truly the best play in NYC right now. It's unbelievably good. If you're in the city while it's running, you can't miss it.
On Broadway, The Ferryman is stellar. American Son is well done if not a bit cliche, but I recommend it, too. Network isn't going to win a Pulitzer, but the experience is really, really cool.
Great season for plays so far, cannot wait for this spring!