What I looked for (and found):
Instructors willing to be friendly and helpful even if they weren't on the clock. No, I don't want to "use" or "abuse" anyone's good nature, but when I speak to someone, I'd like to not worry about phrasing my conversations to avoid asking a question or discussing something that could be considered "stuff for on the clock".
Our private instructor is a most credible, kind, helpful soul. She's actually interested in teaching us to be good dancers, instead of just taking our money, throwing stuff at us, and expecting us to pick it up from there. Our group instructor is a patient man with a good sense of humor- and he HAS to be with people like us in that group!
We lucked up and found a good studio on the first try. I'm SO glad this happened. They take the time to help each student who needs it, and make sure that the group progresses and nobody's left behind. The parties are fun, everyone feels included, and there are no snotty, backbiting gossips allowed. That's one thing they "bounce outta there".
Not much help, I know, but I just wanted to say how proud I am of our studio!