Recently taught through the book of Colossians and this was the most in depth commentary I read. O'Brien is very solid and definitely knows his stuff. It's certainly a technical commentary so a little Greek is probably needed to get the most out of it, but it's a rich resource and O'Brien sheds a lot of light on Colossians and Philemon. This commentary falls on the more academic side so it would work best being used alongside a more pastoral commentary as well (I also used Calvin and Hendriksen and enjoyed both). This one will help uncover the meanings of words, phrases, and passages, the more pastoral commentaries will help you apply those meanings to life. Highly recommended.