The Mountain High pulse system I have been testing is like FADEC for the nose. It is absolutely great. Here is a picture of the system:

I used it on two back-to-back long flying days this week and I love it. To begin with the cannula is much less obtrusive (is has no mustache attachment) and seems to be made out of softer material. I can eat a sandwich without taking it off. Best of all is the O2D2 system. It fits in the console with one O2 hose coming from the overhead. It needs lower pressure than the ship's system so I have a small inline regulator. Then you plug one or two cannulas into the O2D2 and the top mounted controls are easy to reach and see by lifting the console lid. In use, the O2 pulse is very short and it occurs at the beginning of the breath. This conserves O2 and it saves the nasal membranes from too much dry air. Best of all the O2D2 has an internal system and it senses the altitude and adjusts the pulse accordingly. The result is FADEC for the nose. I did not have to fuss with any settings and I flew between 7,000 and 17,000 feet. My O2 saturation stayed between 92% and 96% the whole time. There are a lot more details about the O2D2 but the bottom line is how easy it is to use and how it almost eliminates the drying effects of O2 use

(Oxygen) all comes from the same port, it has the same moisture content, nil. The only difference between medical, welders and aviation O2 is the paperwork and certifications. ... When oxygen is used in a medical setting, after exiting the tank it is sometimes passed through water to humidify it for patient comfort (or more). The stuff in the supply tank is however, bone dry!