Entirely too addicting!
My biggest complaints about the game:
1. No pause.
2. It doesn't resume if you exit the game. This combined with #1 can be annoying if you try to sneak in a quick round at work and get on a crazy good streak that you don't want to stop. But have to.
3. With each pitch, the "center point" of your target area is recalibrated based on where you're holding the phone. This can very quickly and easily lead to "target creep" if you're unaware of it. It should have a standard calibration point.