Mod Bod
Comp Room only shows up if the EZX has the samples for it. It is basically a compressed room mix for the Bonham sound lovers.
Hardly for just the Bonham sound lovers. Using it with the room mic gives you the opportunity to add a subtle or not so subtle form of parallel compression.
If you "whack it up to 10" then your average Bonham fan will be happy, but you can use it more subtly. Parallel compression, particularly on a drum buss, is common in most forms of music.