I use an 850 in a Citation 650 and it is markedly better than the conpany-issued Telex 750. The ear cushions are nice, and not dealing with a batteryuis a plus. I use a Bose X in my piston single and the 850 is nowhere as effective in active noise reduction as the Bose. In terms of dollars spent/value received, I would say the 850 just makes the cut, but just barely.