I've used it quite a bit, and I get the feeling that if you are winning a lot, then the recommended price is a bit low, and you'll be having a full arena just about every game. But that's ok for me, since I've upgraded my arena a lot midseason, and so if the price is a tad too low, I can be assured that those seats will fill.
And when I've lost, the attendance has dropped slightly, suggesting that in most cases the price is pretty close to optimal. Maybe a few more dollars and you'd earn a tad more money, but it might only take a few losses to remove any advantage.