I've been using the Ansco 113 (what Photoformulary used to sell before they switched to MAS - or maybe they still have it) on Ilford MGIV and Gallerie grade 3. The blacks are very good, but it does take longer in the tray which seems to be a potential source of problems with these developers. I'm going to try the MAS formula and just bought some benzotriazole to try the Fein's.
I have not been diluting the Ansco 113 as Mr. Buffaloe recommends, but just using it 1:1 w/out citric acid. I'm going to give that a try too, but I've never had problems with tray life as I usually only work for 2-3 hours at a time, and with a couple of pounds of Amidol on hand I'm not as worried about using it up any longer. Still, economy is always wise.
Please let us know what you find, as, while I do use Amidol on Azo, I'm now switching to it for everything (except, perhaps, warmtone). It stains, turns orange in the fixer, and requires some care when handling the powder, but I finally feel like I am making real prints.
Thanks,
Will