If it needs light duty cleaning or just a touch up thats the best way to go.
For the heavier stuff I use a cleaner similar to simple green. I start by covering up parts that need to be covered. Airbox, fuse box, alternator, distributor cap if equipped, and the battery. I lightly mist the engine bay with water holding it off to the side. Less is more. After I lightly rinse I spray cleaner, I get a soft brush and old clean towels and some elbow grease to start. Then, I rinse again. After you get it to your liking dry it off it real good. A Leaf blower works good for that. At this point I remove everything and start the engine you may get steam not a big deal. Stop wipe up steam. Then I use Sprayway instant shine. Whatever process you use just make sure the engine is cold.