Rush was down in June when I went too the only time it was open last year when I went was FN and it had about 90 min queue so didnt go on it because of the queue length.
Both parks have some great audio for Thorpe Park for me the best audio has to be Colossus and Inferno themes. For Chessington the best audio I like is Vampire. But overall I would say Thorpe has better audio.
The biggest queue I have seen for loggers was on a hot day and the queue was 20mins thought it was a nice amount of time thought it would of been longer.