For the last three seasons I have been using Federal Ammunition's Black Cloud shot shells for hunting waterfowl. Black Cloud uses 40% Federals flight stopper steel and 60% premium steel. It also uses federals flight control wad.
Here is a link to a video that tells about Black Cloud.
I like Black Cloud, I think that it is better than any other non-toxic load I have ever shot. I feel it is worth paying more for it, because I don't cripple as many, or have to shoot them twice just to nock them down. I have folded geese at 75 yards with it.