Whey protein's absorption time is 1-2 hours depending on which source you believe, while egg protein is about 2-3 hours so slightly slower. Whey Protein is richer in Glutamine, Leucine, and Isoleucine, while egg protein has the slight edge in Valine. Whey Protein is much more cost effective at around .65 per serving where egg protein (the powder) is 1.15 per serving. Since egg is slower digesting, a case could be made for it as the better meal replacement option as it may keep you fuller longer. Another reason is for those who are lactose intolerant also may go with egg instead of whey protein.