I believe Maine just used it for presidential. (There was some back and forth in the courts on that; I forget where that landed.) They're the furthest ahead with it.
5 cities just passed RCV themselves last week. That brings the number of significant cities up to about 15, I think, including San Francisco, New York, Boulder, and Minneapolis, among others.
RCV takes a little bit longer to count, but... really, that's the least of our worries at this point. :-)