Over ten years ago the best commentary on Revelation I could find was Mounce (1st ed), then we had his second edition in 1997, followed by the huge works by Beale and Aune, since then we have had other useful works by Kistemaker, Brighton, Witherington and of course Osborne.
Now, Smalley treats us to another scholarly masterpiece. He has already written a commentary on John's epistles (WBC) as well as the book "John: Evangelist & Interpreter". He follows Beale in being a modified idealist following Hendriksen, Caird, Sweet and Wilcock. He regards the author as being John the apostle and assumes an early date, but this is not noticable in his comments. His introduction is short, but he has already published "Thunder and Love" which covers much introductory material.
He covers a section at a time under the headings: translation, textual variants, literary setting, comment, and theology. There are a number of useful excursuses. The commentary is based on the Greek, but the Greek is transliterated. At 633pp he is not as verbose as Beale and is far more readable.
Students now have to choose between Mounce, Osborne and Smalley. He regards the first seal as "lust for power"; Ch 7 deals with the church on earth and in heaven; the two witnesses are the witnessing church; the woman of Ch 12 is the covenant community of God from both the OT and NT; Babylon is worldly, idolatrous, oppressive powers; on Ch 20 he is amillennial. This commentary was a big treat for me, another very useful contribution on the book of Revelation. It is a delight to read and I am still working my way through it.
From famine ten years ago I have now become a glutton. NB. If I had to chose between Mounce, Smalley and Osborne, I would go for Osborne (Revelation (Baker Exegetical Commentary on the New Testament)