Baker's commentary is very brief. This would be an excellent guide for a Bible study leader or pastor without much training in biblical studies. For more detailed exegesis, I recommend O. Palmer Robertson's NICOT or Waylon Bailey's NAC. This would provide a nice supplement to those volumes.
Baker takes a conservative, evangelical approach to these three minor prophets, selecting what he considers to be the most important information for the basic interpretation of the books. He defends the unity of each book, along with the traditionally ascribed authorship, dating all three books to the traditional period of the 7th century.
Baker is broadly Wesleyan in his theology, and I am more Reformed, but I did not find much in this commentary that I disagreed with theologically. At most I would have worded things slightly differently. Baker thus tdoes well at capturing the theological message of these books without trying to score points for his particular viewpoint. He simply discusses what the text is saying. He has room for enough linguistic, textual, and background issues to show the general sense of what the text is saying, even if he does not always give full details on matters that have a smaller effect on the overall message. A more detailed commentary would be required for that.
I know of no work at this level that does as good a job, even if it turns out to be not even as detailed as a number of other volumes in the Tyndale series, even the other minor prophets volumes. I would not prefer to have to teach these books with just Baker's commentary, and there are a lot of good commentaries on these books, but this is one of the ones I want on my shelf. This may well be the lowest price-to-information ratio among the evangelical commentaries.