First off, I really, really, and I mean REALLY hope it is better than Legend of the Seeker. Now that I have that off my chest, my only concern would be the show catching up to the books. He has taken so damn long to even finish Dance with Dragons, and he seems to be more interested in blogging and his Wild Cards than anything else.
My favorite characters would have to be Tyrion, Arya, and Jon Snow. I absolutely loathe Sansa.