Best Gospel of John commentary as textbook for seminary course?

Next summer (2011), I am teaching exegesis of  the Gospel of John for Asbury Theological Seminary and I will require students to work through a commentary (as one of a few textbooks).  I am undecided, as I want something extensive, but engages well in theology and ethics (and not just historical and philological details). I welcome you to participate in my poll (below) keeping in mind this is for seminary students (primarily training for ministry) [i.e. longer and more complex is not necessarily better].

When you make your choice in the poll, if your opinion is strong, I would appreciate if you give your reasons for your choice (or against the other options) in the comments. If you think there is a better one out there that is not on the list, do share with a comment. Thanks for your votes!