When I rushed (like 6 weeks ago) I got there at 9:30 and was like 6th in line and got a good rush seat. You should go see it. Don't listen to the haters. If you like musical comedy you will have a really good time!
I went today to catch Chester before he leaves on Friday. I got there around noon and ended up with front row seats so you'll be fine. Some of my friends were in the mezz in G and they said pretty much every row behind them was empty.
I went in with no expectations and kinda enjoyed it. I went to the box office at around 4 or 5 and the rush seats were 4th row left orchestra. I didn't have enough cash, so I got the 36 dollar rear mezz seats instead and moved up.