Egg whites has has far more complete Amino Acids profile over Whey. its .97 vs .92 in Whey.
On the other hand about 75% of the whey protein is consumed. Say you take according to the nutrition chart 25 grams in one scoop, you actually got about 17-18 grams only. In the egg whites 1 cup wjites is worth about 40 grams of which your body consumes about 36-37.