S&P's outlook, described in a press release before earnings came out, is neutral at "$23 per share". Now, as always, that's exactly the market price at the time, so you can't take the number literally. But if you read the release very carefully, you can get a feeling.
My own opinion is that the stock is probably fully valued over about $18. It would probably be solidly undervalued at $10 and would probably be solidly overvalued above about $35.