I saw it at the Dubai Airshow. I heard the guy talking in it, when I was wearing a conventional headset, and it was crystal clear. One good thing, you don't get the ssssss sounds nor inhalation/exhalation sounds, but if you are eating and have intercom, it will go through the system (I have heard).
Another good thing is you can keep it on when donning oxygen mask. Since it takes the sound of your speech from the ear directly, you don't need to use the Oxy mike, and sound is still as clear as with no mask (should be).
But no, I haven't tried it. I couldn't, because each set is made to fit one pair of ears, so you cannot try it before you have one made for you specifically. You have to rely on people who have bought it to rate it. I believe certain airlines have it on test?
I am just as curious myself. Presently, I use earplugs, ones with a hole in the middle, so you can wear them under headset and still hear what you need. For 8 EUR a set, it is a splendid alternative to expensive and batteryconsuming ANR headsets.