Horacio said:
The first classless, maybe. The first gun rules, not at all.
Correct me if I'm wrong, but I don't think he meant to imply "first gun rules" also - the DMG has those. It's an easy mistake, because of the ambiguous wording, though.
(Did you know how much I had to go through to get those "classes" into PCGen???
)
My opinion is that the d20 version is well worth it, if you plan on doing ANY modern day gaming. The following is a list of genres the d20 COC book is useful for:
-Cthulhu gaming
-Modern Day General horror / "X-files" style gaming
-Modern Day non-horror gaming
-Inserting the Mythos into D&D gaming
-Just looking for high-level challenges for your D&D PC's
-any classless d20 gaming
The basic character rule is simple: besides the six attributes, you have four "stats" - Attack bonus, fort save, reflex save, will save. Choose which two are good, and which two are bad. pick your skills. End of story. You can't get much more classless than that.