I just tried Progold, received it yesterday, I ordered a 7-ounce container. One thing that impressed me is that it's 40% protein! It also disintegrates in about 15 minutes so it probably doesn't have all the stabilizers that allow other foods to retain their shape "indefinitely".
My fish seem to like it as much as the Hikari pellets I fed them before but I had to squeeze those to get them to sink

I have no problem getting Progold to sink.
I've also tried Bioblend (when I first got the fish) but the pellets are very small and it has ethoxyquin as a preservative. On this forum I've read that ethoxyquin can be carcinogenic to a fish. Heh heh, the fish liked that too though!
I think the price was around $8 (US). I will probably order it again if I can't find anything at the local store with 1) high protein 2) no color enhancers 3) no ethoxyquin and 4) sinks without being squeezed.