The Bose are very good indeed.
One thing which cropped up on one of the aircraft mailing lists, though, was that they're not intended for unpressurised high-altitude use. The official upper usage limit is 14,000ft and above that it's apparently not uncommon to suffer acoustic feedback. I've used our pair up to that pressure level without any problems, but I've never had them in use above there, so can't comment myself. Perhaps others have experience they could share.
Of course, if your aircraft is pressurised, it's not a worry. Actually, maybe that should be, WHILE your aircraft is pressurised it's not a worry.