greenbaggins
Puritan Board Doctor
If you are asking for a volume on Ephesians that is substantive yet not too technical, O'Brien is not actually where I would go. It is an outstanding volume, plagiarism issues notwithstanding (nothing normal will induce me to part with my copy!). Sinclair Ferguson and Richard Phillips are the ones I would go to for the level you are looking for. There is also Uprichard's volume in the study commentary series, which I found solid.