I’ve been flying professionally for 16 years now, and my preference is to have a passive noise reduction headset. I use the David Clark H10-66 everyday, I moved away from noise cancelling types. I’ve previously used both light speed and Bose, but couldn’t be doing with continually replacing batteries and ear muffs. I do seem to be in the minority at my company though. -27db is pretty damn good if you ask me though. For me personally, passive noise reduction every time, so I highly rate the H10-66.