We used Antler King when we were managing a wild herd in Alabama. Had great results, we had buck fawns with spots and small 4 and 6 pt racks.
Nutritionally I think it worked well, good amount of fat on all of our does and they were all producing well.
But we were using it on a wild herd and with some mineral supplements, mainly trophy rock and Vita-Rack 26
The drawback for us now is availablilty. When we were using it it was 8.50 per bag, now it it upwards of 13 everywhere I have checked, also it is hard to find a supplier, ours is the local co-op but they only order it when someone requests it.