This is an excellent commentary. Full of great info that makes a big difference to what you know and what you think you know about Mathew. It is also written in such a way that it is not difficult to follow, yet rich in detail. Osborne is clearly a Christian believer and not only an academic. Why four stars and not five? Because he follows the modern trend of disparaging certain verses which the KJV lineage of bibles includes, and which I believe are part of God's Word. For that reason I consider this an imperfect work. If this does not trouble you, then I should say you are unlikely to find a better commentary on Mathew.
From my evangelical perspective, and from someone that wants to dig into each line of Greek but without too much competence in original languages, this is superb. Each section has a sentence flow diagram, an over-view of the section, a verse-by-verse breakdown, followed by a short and helpful application thought. It is well researched, written well but then, joy of joys, the formatting (at least in the hardback book version) is excellent. It is recommended by the usual suspects for Biblical Exegetes and Reformed Scholars. Not just thanks to Grant Osbourne, but thanks to whole team producing the Exegetical Commentary series. Really good.