i've tried that but it doesn't work as well for me. i've use 2 different kind of engine degreaser and it doesn't shine. but then! i never tried simple green which i'm sure it would work.
The "shine" attracts more dirt to the engine bay. Simple green will give the "fresh the factory" look to the engine bay, or as close to it as possible. Also, navel jelly does a good job of removing oxidation from blocks and other metal surfaces in the bay.