I've always found ON to be the best. It doesn't clump, tastes good, cheap, blah blah. Most whey protein comes from the same basic sources (liquid byproduct of cheese production, etc) The whole "micro-reverse osmosis'd-mitochondrized-gyroscope filtered" craze only pans out to slightly higher bioavailibility (often overstated by labels and advertisments)and twice the price. You can order pure whey powder, only difference is you'll be adding your own filler (i.e. fruit) to make it more drinkable and possibly healthier than the premixed stuff.
As for NOW, they are reasonably priced, cost more than ON per g/prot but not by enough to make a fuss...I don't care for the flavor, but you can always ask one of your buddies to bring you a "sample" before you go out and buy it. As a general rule if it can't mix in a shaker without clumps or doesn't taste reasonable I don't want it, but thats just me.
PS ON has some prot concentrate (the 4th best they were talking about I assume) but that is #2 behind prot iso which is the good stuff.