I like only "whey protein isolate"
whey protein concentrate usually means "we made this as cheaply as possible"
has a non flavored whey protein isolate that is pretty inexpensive. it's probably bought from a good source. i like it.
my favorite is "jay robbs" protein isolate. it is plain or sweetened with stevia.
also, it's expensive BUT!
...The cows are not treated with any nasty hormones or junk. The cows are grass fed & treated humanely which is important to me. It's the only mainstream whey protein to do so! goat protein is really good but expensive too.
Other good whey protein requires buying online.
avoid anything with phrases like "Lighting Bolt 9000 Muscle Mania" ....