He is not a legitimate MVP candidate, but he's a shoe-in for OROY at this point.
Recency bias is amazing, though - everyone sees RGIII and pretends in their mind that they didn't feel as strongly about Cam last year. They justify it by coming up with justifications to support the recency-biased view that RGIII MUST be having a better season.
The truth is that recent NFL history is littered with mobile quarterbacks with new deliveries in new systems having a successful season, after which teams have collected enough tape to counter them. This happened with Vince, it happened with Vick's resurgence and it happened with Cam. Teams need time to develop the schemes and approaches to defeat their versatility.
RGIII could be different, but remember we said that Cam was different. The "overhyped" comment is true in that RGIII's long-term potential isn't going to be proven this year. It will be proven if and when he sustains this performance after teams have begun to adjust to his style of play.
But man, does he look good, and man is he a likable guy. I'm an RGIII fan. /shrug