I'm starting to think that it's not so much the species as what they've been eating and where they've been. I've had canvasback, bluebills, and redheads that were great and mallards and pintails that tasted like mud. The only exception is goldeneyes, they always taste pretty strong and I will go out of my way to not shoot them unless they are the only thing flying, and then they get brined for at least 3 or 4 days before I even think of eating them. A key that I've found with divers is to make sure that you get all the fat off the meat, it's not the meat that tastes strong so much as the fat and skin.
Avery- the K-Mart of waterfowl gear.