Unfortunately STV has the same problems as first-pass-the-post, and some actually worse ones. Which is unfortunate, because people don't understand that and think it's much better.
It has some of the same kinds of problems that approval has, given that approval voting is a special case of range voting with only 2 options, 0 or 1. But I think it's better than all of the others, and much simpler to implement and understand I think.