Bwipilot:

I have flown on the 737, 320, and 757 767 at United. I personally love having ANR. Currently on the 320 it's not needed but I still put it on and enjoy it. I am using the DC Pro X because I grew tired of waiting for the UflyMike setup to come out. If your friend is a commuter then I say without a doubt get the tso UFM on the new Bose headset. If they fly international then once again I would say UFM because they can use it while taking their brake and then plug in again after break for comms (752 recirculating fans are loud in my opinion) If they are in the 737 and do not commute then I would think the DC Pro or A20 would be nice but single purpose.

I had a pair of ANR DC's from 1999 that I was using until 2015 (~11000 hours of use) when the headset bracket broke....they still work just need to send them off. I like the product and find them to hold up well. I have the DC Pro for a year and think they are comfortable. At the end of the day I still have a Bose QC25 for personal use when deadheading but originally bought them for commuting.

Hope this helps.