It's the patching that's the big issue for me. Even if it's from a good developer, every game has small and large problems that'll need to be fixed, and I'd rather not sink my money (more money than I'll spend by waiting a few months) into a product that still needs to have the kinks worked out. I think half the reason I enjoyed ME3 as much as I did is because I waited a year and change to play it.
I'm not big on multi-player, so this might be less of an issue, as I'm just holding out to do single-player run throughs, not co-ops with my friends.