I recently bought a Bose docking station for my Ipod which is superb with great sound so I can only imagine that the Bose X must be as good. Am I correct?
At the moment I am trying to justify spending 275 quid on a set of Bose QuietComfort 3 (noise reducing) headphones. Although these are for music not aviation, the sound quality is like nothing I've heard elsewhere, really top notch. It certainly sets a standard for performance in their other products.
The only thing that put me off Bose was that primarily they are a marketing company rather than a manufacturer. Almost everything else they produce is over-hyped and over marketed (Sunday supplements anyone?).
IMO Bose are not just a 'designer brand'; they produce top quality products even if they do waffle in their marketing literature

. If the QC3 headphones are anything to go by, I would imagine the aviation headsets are some of the best available too.