i use the Fastfire primarily for slugs - ive used a setup like this for bear and boar, slugs arent my first choice for deer and ive never shot an animal with buckshot in my life... i just stock up on it for when the zombies come
for quick shots on moving targets with
shot, IMO, nothing beats point-shooting with a simple bead sight. i would
not recommend something like this for waterfowl -- but perhaps someone with more experience in this can give you a definitive answer on that, im not really interested in waterfowl.
ive had it mounted on three shotguns - an H&R Ultra Slug Hunter, a Savage 24F and a Mossberg (smoothbore). i think this is close to the ideal sight for a slug gun. i also had a Benelli with factory ghost rings with Tritium inserts, and the Burris Fastfire is, IMO, easier to see, faster, almost as small/unobtrusive, and almost as durable (though i havent tested bashing them against something, this is purely subjective lol). it will also probably be significantly less expensive to fit your gun with than a set of good ghost rings (and no, a clamp-on heatshield with 'ghost rings' doesnt qualify, hehe).
you can buy them at Lebarons or other Canadian distributors, but the price is something like $280 Canadian.
in the states you can get them for $180 US, but you will have to ask and make sure there will be no import issues (i dont know).