I have one tip:

Every time I un-plug the N9 from the charger (full or partially charged), set Airplane Mode (Flight Mode) On, wait some secs and then turn it off.

This action will remove, and then add again the "SIM" icon on your app-grid screen, so some meego process that (working faulty because some bug) will be stopped, and then the battery consumption will be normal.

I've tried several times not using this method and, after several minutes, in the Battery Monitor App, Meego System is draining battery like hell.

Hope it help!

Just for the record:
Running Meggo PR1.2, Bright 80%, 2G, Wazzap, 1hr MfE => 36 hrs of battery life.