I was out shopping.  Only, the Sony WH-1000XM4 and BOSE 700 were available to compare. Contrary to some reviews I read, the units are somewhat different in their effectiveness. The music available was not very useful, likely the 700 sounded a little more open. The critical part for me is the noise cancellation effectiveness. Neither was stunning, but the Sony was noticeably more effective for canceling low frequency energy from the air conditioning system and noise leaking through was more natural sounding with the Sony. In “Ambient” mode (conversation is passed through) the 700 sounded much more natural. I wish that both units would mechanically block more noise, but this would result in heavier, tighter fitting units, “heavy” and “tight” reviews, and market failure.

I settled on the Sony, but have not yet used it “under fire”.

Another contender would have been the Apple unit, but it was not available for demo and it busted my budget more than the Sony. Easily replaceable ear pads would have been a big plus for the Apple.