Revised Expositor's Bible Commentary worth getting if you have the original version?

I already have the original Expositor's Bible Commentary, and I'm considering the Revised version. For those who both sets, are you finding a fair amount of updated material for the authors that were in the first version--as in Carson, Salihamer, Ross, Longenecker, etc? I can see the value in getting the volumes written by the new guys, but I'm wondering how much of a revision the revised versions actually are.