Coffman is quite the character. He's outspoken and strongly opinionated, so sometimes he cracks me up with his jabs at things he considers false doctrine (even when I agree with his assessment). These books are verse-by-verse evaluations and comments on the scriptures with analysis and outlines in some places to help you understand things better. My favorite bits are the outlines of parables. These books could be better (they need editing at least), and they aren't for the faint of heart (sooooo much detail!), but they're valuable if for no other reason than that they make you think.
This is a very good commentary on the Gospel of John. I particularly like Coffman because he quotes from so many different sources. Having his commentary is almost like having a collection of commentaries on the book of John. I recommend this commentary to every Bible student.