This is exactly what a commentary should be. O'Brien does an excellent job of approaching the text from a solid, evangelical, and scholarly viewpoint, without being overly technical in terms of textual criticism, greek syntax and grammar.
Every week I read the corresponding section to prepare for my sermon, and I always gained new insight into the passage as a result of reading this commentary. Though O'Brien doesn't focus on application or specific homiletical insights for preachers, he does such a good job at exegesis, I found that the application naturally flowed out of a better understanding the text.
I would highly recommend this commentary (as well as this series of commentaries) to anyone who wants a deep understanding of Ephesians.