You might find The Text Of The New Testament, It's Transmission, Corruption, and Restoration, (mine is the fourth edition) by Bruce M. Metzger and Bart D. Ehrman more useful.
The main differences are that the Commentary actually deals with the finished product of the United Bible Societies' Greek New Testament, and is actually sold as a companion for it. It deals with a lot of actual Greek, though there are some sections of the new testament that have what I consider good English only (or mostly English) write ups (those are the reason I bought it). I do not read Greek (do good to read English, and only good up to about 4 letters with it
The Transmission, Corruption, and Restoration is much more English friendly. About the only Greek is in examples of some of the early text types and to show how Greek letters can be mistaken for each other, that type stuff. It deals more with explaining how errors crept into the new testament, methods of determining what the earliest text likely said (textual criticism of the new testament). It gives a very good history of the new testament and the methods used to record it over the years. It also has a good write up on the ending of Mark.
Guess I might as well mention another related book. The Text Of The New Testament, An Introduction to the Critical Editions and to the Theory and Practice of Modern Textual Criticism, by Kurt Aland and Barbara Aland, Translated by Erroll F. Rhodes (my copy is of the second edition). It is more like a text book for a course on textual criticism. It covers some of the early attempts at determining what the original Greek texts said. It goes into the various ancient manuscripts of the new testament that are available today, how they are identified, their history. It's not a bad book, but I found the Metzger/Ehrman book much more enjoyable and generally more informative for my purpose.
Hope this helps you pick one you will find useful.