You get the "bump an old thread" award for the day ha, ha. I've actually been using the ATH-ANC23s on flights lately. Paid like $26 for it. They work pretty well and sound good. I've not tried the RE400 but I used to have the Titan 1 which I believe is the same as EX1. You''re talking 2 different signatures with those. I sold the Titan 1 due to hot treble (at least to my ear). The ANC23 is more bass heavy and has a more polite treble. With ANC off on the 23, they isolate about the same which isn't much. If ANC is important, obviously the 23 is the one to get. For sound quality, the EX1 would be more open, balanced and detailed if you can handle the treble.