I doubt WotC would publish a book unless they felt it was good and saleable, so the question for those with that discerning caveat might require a bit of conjecture in regard to how much they are likely to find to their own personal tastes.
As long as they maintain the current level of quality, I'll buy 'em. I expect the hardest sell in this regard will be the DMGs, but I didn't expect the DMG2 to be as good as it was, so who knows?