I run with the manta that "fresh is best". That doesn't mean I hate frozen products... my mantra can refer to fresh peppers or tomatos straight from your garden or from the local farm market, or it can mean fish processed and flash frozen at sea within a few hours of catching. In both cases, few hours passed between the time of death/picking, and purchase/consumption. Freezing is a technique for preservation, not modification.
However when you process something into a state that lasts longer, such as the 5-10 year lifespan of dried eggs, you certainly are going to loose some flavor, as with powdered milk. Sure, it will provide an echoing similarity to the product you know as an egg, but the full flavor explosion will not be there. I believe the process of eating should be more than to provide nurishment, but to make a person happy, and allow them to enjoy the meal. To quote Alton Brown, "Powdered eggs are not good eats".
In cases where you encorporate eggs for their chemical properties (such as binding) I'd say you will enjoy the end product more. so make cakes and pies and perhaps even quiche ( although I never tried it) to your hearts content with powdered eggs). However I would never attempt to reconsitute them back into a form that we once called an egg. not scrambled, not an omlette, never!
Arky hit it spot on with the shake. In my honest opinion, Eggs were powedered into a dry product for a singular purpose... to give all the bodybuilders of a world a safe way to get egg protein without needing to risk samonila poisoning! :) There are more ingredients to provide flavor in the shake, and the eggs are there for the protein which wasn't baked off.
-Matt F, Gourmet.
Lifelong foodie taking back the title Gourmet.