I had the chance to try Nebia for myself yesterday at their headquarters in San Francisco's SOMA district. (They were in a celebratory mood; their Kickstarter campaign had just crossed the $2 million mark with an original goal of just 100K).
I helped myself to a clean towel just outside their bathroom, and took a shower (an ever-so-slightly awkward move in someone else's office).
It was like showering in the middle of a cloud. I was enveloped by awesomely warm, moist air. But for those of you having any doubt about the force of the spray, don't. The velocity with which it comes at you is powerful. I shampooed and rinsed in the same time as in a regular shower.
When I got out, there was no awful blast of cold air. The entire bathroom was warm. I felt like I was at a spa, and the feeling continued long after. For the rest of the day, I kept touching my skin—it was so hydrated! Like I'd just gotten back from a day at the sauna.
You can order Nebia now (it'll cost you $299), but you're going to have to wait until May for it to arrive.