Hi everybody - I pushed the 1.3.0 release out, which has much better racer support (just better default gains, in fact). Please update your QGC version, flash the latest stable and RESET your airframe configuration (which will keep your RC calibration, but reset your gains to our recommended defaults).
Make sure to use the QAV250 or 250 generic (if you fly something other than a QAV 250) config and give us some good feedback.
The 1.3.0 release is in a "soft release" state, which means we might still make amendments - so any flight testing you can contribute will help us a lot in ensuring we made the progress we wanted to make.