I'd say that from everything I've read, quartersawn wood is the standard for high quality acoustic guitar bodies, no question. The neck though is different, and I've seen postings from people that know indicating that flatsawn for a one-piece neck may be better as it flexes properly and predictably. But for a multi-piece neck, I would think that advice is out the door. The multiple pieces are going work against each other and produce less likelihood of a warp, whether flat or quartered.
As for matching grain, I agree that it is required for a high end, quality built instrument unless it's a painted finish. The straight grain stuff is preferred in the acoustic guitar market for its stability, although the wilder stuff has its place for cosmetic reasons.