TL;DR: Great product with loads of helpful stat blocks, could use a few more editing passes.
The books offer a truly incredible number of stat blocks and the four levels for each monster make tweaking them on the fly much faster. The monsters are generic ones from popular RPG systems so if the judge wants more DCC style monsters they would need to use aid books (Monster Alphabet) to make them more unique.
Each monster having four "levels" also means you can change an encounter or monster's difficulty on the fly or change published material’s level range.
My only complaint (and reason for four rather than five stars) is that some of the blocks lack information (save DC's) or reference incorrect ability scores/saves where the product has been copied over and converted from the versions for other systems.
From a price vs content standpoint though this can’t be beaten and well worth having on your shelf.