When my copy of Gordon D. Fee’s IVP commentary on the Epistle to the Philippians arrived I was asked what the difference is from the NIC commentary. Fee describes the difference in the Author’s Preface (p. 9-10) so I thought I’d share part of his answer here:

More years ago now than I should be willing to admit, Jim Hoover, my former student who had become editor with InterVarsity Press, invited me to edit a new series of commentaries that IVP was interested in publishing. I was writing my 1 Corinthians commentary (New International Commentary series) at the time, so wisdom dictated that I decline. But when pressed at least to contribute a volume, I agreed, “as long as it is one of Paul’s shorter letters!” So we agreed that I should undertake the Philippians volume in the series.

A few years later I was approached by Eerdmans Publishing Company to succeed F.F. Bruce as editor of the New International Commentary series. This time I agreed; but when the Philippians commentary in that series came open and the publishers approached me to write it, I faced a considerable dilemma. The editors of IVP graciously agreed to my request to write the NIC commentary first, and for this I owe them an enormous debt. Now the shoe is on the other foot; for it became clear in the process of writing the smaller version (what I came to fondly dub “Little Phil”) that it would be impossible for me not to repeat myself over and again. So now I am indebted to Eerdmans for their generosity in allowing me to use many of the words published elsewhere.

Fee goes on to explain (in 1999) that the two commentaries are s lot alike with the IVP version being more user friendly per se. This makes the IVP a useful addition to the NIC although according to Fee the basic content didn’t alter much.