I've updated the APM Beta code (zip file version) to roll up our latest bug fixes and tweaks. The most noticeable one is that we've moved back to the excellent circle algorithm that we had in ArduPilot2.7 (we were experimenting with a different approach with APM, but the ArduPilot one turned out to work better in the real world). You can see some results from one of my flights yesterday above (using a SuperStar--moderate wind).
Overall it's flying very well and has been tested on a large and growing number of aircraft. It almost invariably works right out of the box with the default gains. All you should need to do is change the DIP switches to get your servo directions right and use elevon mixing if that what you need.
This is the last beta update. We expect to release the 1.0 code (not beta) this time next week. As always, you can follow the progress here. As you can see from that activity tracker, the APM Dev Team has been busy.