Airplay is awesome. iPad or iPhone anywere in the house and you can dial up Pandora, Rhapsody or iTunes and listen without having to plug in. It's like Bluetooth but easier. I imagine since Apple is doing it, we'll see more use for video and other programs.
I have a SC57 and have definitely "tweeked" myself to death. The MCACC software sucks and creates a bright presention. Then you have Onkyo's sketchy reliability.
Have you looked into the lower Denon line? They have Airplay, good software and reliability.