Decipher is the definition of failure in RPGs, CCGs, etc. There is a reason you got those books for such a good deal. I saw the whole line for sale at Gen Con last year (new) for $6 a book. It's a horrible system and it's also an unsupported system at this point. They stopped producing the line in 2007.
Yeah, I found the Decipher Trek RPG to be subpar. However, the Star Trek CCG is amazing (especially the First Edition).