Normally I prefer to see the TV/film before the book anyway, Battlefield Earth remains the only book I read after the film and thought was worse than the film - which by the way is an indicator how bad the book is, not how good the movie is, which is like comparing STD or Cancer types.

So I won't be bothered if the series ends first (unless its via cancellation rather than finish) even if it seriously varies, and if the book and show both come out in a reasonably similar time frame with book first I might even hold off grabbing a copy until the show rolls out. I mean I never finished Hobbit and it was on my to-do list and I shelved it until after the films are all out, so I'm willing to hold off reading book 6 and 7. But I will actually be a bit surprised if book 6 isn't out by the time the show reaches that zone. I would bet on at least one of the two books being timed to come out with a season anyway.