To clarify why, I've been an xPAP user (CPAP, VPAP, ASV) for over 3 years. For whatever reason, despite good numbers after an arduous journey to using it successfully, I just don't feel awake. It's like xPAP only helps about 50%. You can search for my old threads if you want to learn more.
Anyways, this is quite honestly just something my doctor and I are trying. I think CPAP would still be the first line of choice for anybody for treatment, and it'll always be better because you have data that you can track. But if for whatever reason it's not working, another alternative is good, maybe.
I've also tried a dental appliance, which only dropped my AHI from the 40s to the 20s, so I figured it wouldn't be too much of an adjustment trying to sleep with this thing. My initial sleep study with CPAP was not fun!
So, if you've never heard of this machine, it works by negative pressure rather than positive pressure. It sucks up your tongue to the top of your mouth, which creates space behind your throat. CPAP "pushes" your throat open with pressure, the Winx "pulls" your throat open. This is another reason CPAP is probably better for most people, because you can almost always find a positive pressure amount which opens things up, whereas I think the negative pressure can work for some people, but not others. I'm not a doctor or a scientist, this is just my impression as a long-time xPAP user.
This is the thing you wear in your mouth:

It creates a vacuum when you 'seal' your throat. When you swallow, the back of your throat closes, and then the vacuum will keep it closed. (It may not close or stay closed for everybody, I think) Then the vacuum will slowly pull your tongue up and keep it there - you can feel this happening. It's a pretty weird sensation at first, and it took me a little time to get used to it. But after a while it didn't feel like something that would keep me up.
I had to take it out a few times overnight to "reset" it - it felt like I had to give my tongue a break. I think it would be something that I'd need to do less and less over time, maybe not at all - just guessing here.
In terms of sleep, I probably got about 5, maybe 6 hours on my sleep study. That's pretty good for me - I don't tend to sleep well in sleep studies. The sleep felt okay, considering everything. I'll have to see what the sleep study says in terms of breathing issues, desats, and arousals. My impression right now is that I'd probably want to try it for a few weeks and compare it to CPAP. At least, I can't think of anything more to try with xPAP. I've tried everything I can think of with it.
Anyways, that's my experience so far. When I get my sleep study, I'll post the info from it.