There is so much crap out there, it is hard to tell. Beatnik made a good point about shatting. Having it lab tested is really the only way to know for sure. If you spend some time on this site, I think you will agree with most veterans here who've "been there done that" with most supplements out there and jump on the Biotest products.
I believe their products are of the highest quality. You will end up paying more for their products than you can get others for, but you know what you're getting and it works! It took me a little while to realize they're not the run of the mill supplement company. Ask yourself this question: "Can you go down to GNC or The Vitamin Shoppe or other supplement store and walk out with a tub of Metabolic Drive protein powder?" The answer is "no". They have not sold out to the almighty dollar. If they had, they would've "cut" the protein with cheap fillers (like a LOT of other companies are doing) and made their products available to the masses at every supplement chain out there. Because they don't cut their product, they simply would not be able to compete with the others.
Protein costs alot more money than sugar. Brand X claims 23g protein per scoop but really contains (let's say) 10g protein and 13g maltodextrose or something. For all I know, it's even less than that. That stuff is dirt cheap. They can sell low and still make a profit, because you're getting mostly cheap sugars. Your muscles know the difference, though.