I got a chance to playtest The Art of Power last month at the Meetup of Doom. My three playtesters, all game designers, took to it pretty quickly and most of the mechanics behaved just how I wanted them to. I'm pretty confident at this point that things are on the right track.
I'm going to be running a couple more sessions over the weekend at Dreamation, which will hopefully put some final polish on the initial playtest rules. The next step after this is to finish writing them up and get them out to some select groups of outside playtesters.
I'm so excited about the game that I've already started working with an artist and the playtest materials are going to have some great art. They will be pretty finished looking, actually. I definitely got ahead of my usual schedule on this one.