Ooooooo.
I'm intrigued.
Are the Demonomicon and DSCC done the same way? or do they also have alot of *smack: take damage. your turn.*?
Every monster manual or book with monsters has *some* monsters that basically act in their own turns, hit you and do damage. Often they'll be those of the "brute" monster role.
One of the reasons the DMG advises mixing monster roles is to ensure a more interesting fight. You add a controller to mess with the PCs, a leader to heal the monsters, skirmishers to out maneuver and flank the PCs, soldiers to mark the PCs and hold them back as needed and lurkers for some nasty hit and run type tactics. Not every fight is going to have every type, but generally you'll want to mix it up.
And that was written with just the MM1 monsters in mind. Everything written from the MM3 and on has really amped that up by giving monsters more reactive abilities, properties, etc.,.
I've only paged through the DSCC but the monsters in there looked like they were made with the MM3 approach. The Demonomicon is not a monster book per se, but it does have some monsters in it. It certainly doesn't have the monsters per page ratio of a Monster Manual. It has monsters, but also a ton of fictional information about where they come from, what they're like, etc.,.