I'm an ex-arena football player. I used whey protein in plain oats 5 times a day for 2 years straight and gain 48 lbs naturally. It works. It's not that the whey itself works like magic, any quality protein and clean complex carb source will help you gain muscle. It comes do to calories in + calories out. I personally wouldn't get caught up on hydrolized vs isolate vs concentrate. I literally would choose the cheapest whey per gram of protein and had amazing gains. Think, back in the day before supplements, bodybuilders would get huge with eggs and meat. eggs score a 100 on the bioavailability chart. The any form of whey is higher than eggs. If they could get huge on egg protein, do you think the type of whey will make the difference in your gains? It'll end up being a combo of all the little things done correctly daily.