See this post for Scot Mcknight's recommendations concerning commentaries on theGospel of John. He lists:
R.E. Brown: The Gospel According to John (I-XII) (The Anchor Yale Bible Commentaries).
C.K. Barrett: The Gospel According to St. John: An Introduction With Commentary and Notes on the Greek Text.
Leon Morris: The Gospel According to John (New International Commentary on the New Testament).
G.R. Beasley-Murray: Word Biblical Commentary Vol. 36, John (revised).
C. Keener: The Gospel of John: A Commentary - 2-Volume Set .
D.A. Carson: The Gospel According to John.
A. Köstenberger: John.