A point on compatibility: if you have four folks with their own various brand headsets in an aircraft, you can reckon on at least two folks finding the volume too high or too low.
More insidious, you'll find that one or two folks can't be heard over the intercom.
It's all down to earphone and microphone impedances. The problems can occur between almost any two models (even different DC models).
It can (in theory) be fixed - a friend and I have done it - but that involves playing with resistors and capacitors to find the right values to "balance" the various headsets. We know the values to use for some types (when fitting the ANR mod).
So choose carefully...