I've read some things that say that staying one OS behind the current one is more stable because it isn't constantly being updated and most, if not all, of the problems have been ironed out. Windows XP is still more stable than Windows 7 or 8, for example. That said, should I upgrade to ML when I receive my Air? It comes with the free upgrade program. Speaking of which, if I do upgrade, how is it done using the free program? How does Apple know you qualify for it and how do you initiate it?