I've read the commentary through John four and am not sure if I will continue using it. I am reading Carson (PNT), Morris (NICNT) and Morris' "Reflections on the Gospel of John" (Great if you can get it)as well as a few others. My experience with this particular work is that it is a summary of other authors (especially Morris and Carson). If you are looking for a compilation of other scholars, then this is a handy resource. If you are looking for fresh eyes on the text, I think you will be disappointed.
I must admit that I was looking forward to this commentary on the strength of Kostenberger's previous scholarly output. I am mildly disappointed with the results. Although he is excellent on many points, I feel at times as if this was a rushed work, not really given the attention that the author is capable of bringing to bear on the text. I would really like to see a thorough revision in the future, perhaps when the professor's schedule is not so full. This could (and should) have been a signal contribution to an excellent series.
A very well written commentary on this Gospel; but is not as detailed as other academic commentaries on John. Kostenberger has provided the reader with vital information; but in a concise way. He deals with most of the textual issues that are raised; but when it comes to explaining the text in details he falls short. He fails to comment on the Pericope de Adulterer (7:53-8:11) and only gives a brief summary. The exegesis is complimented with footnotes and additional notes which are very helpful. I recommend this commentary as a secondary one on the Gospel of John as there are a lot of helpful notes.