The Transcend is great. The waterless humidification is amazingly bad. I'm not sure why, but it's designed to be extremely loud on the inhale. My wife says it's as bad as my snoring. When I've tried to use it, I unconsciously hold my breath until there's no choice but to breathe, and then the noise ...

I have the Transcend II and I love it. I've used it two nights consecutively on one battery charge so far. It's utterly silent (if you don't have the HME waterless humidification system). I don't wear it on my head, but I have kept it on the corner of the bed next to my pillow with absolutely no pro...