I think it is potentially good but is going to have great trouble getting in the door. The biggest problem I see is the reliance on advertising. I don't know how schools will like having ads fed to their student computer screens constantly. Say what you want about Windows but it is controllable to a very large degree.
There is also, of course, the fact that so very many teachers are not tech-savvy and are, in fact, not just resistance to change but completely negative about it. I've tried sharing little free aps and those have been shot down. I can't imagine trying to sell a whole new OS!