My wife has been using NeoRhythm for insomnia for about 2 months now.
I don't want to jinx things, but so far it's been a Godsend.
My wife had had terrible insomnia for about 1.5 years prior to that. It got to a point where she might sleep 3-4 hours a night almost every night of the week, for weeks on end. We got to a point of total desperation. We had tried most available solutions: sleep hygiene was fine (stuff like abstaining from caffeine and blue lights). Sleeping pills are not a permanent fix, so we use those very sparingly. We had been trying meditation (using Muse) for about 2 months, and it wasn't a huge help.
Since getting this device 2 months ago, the insomnia has gone from about a 8 out of 10 down to about 2 -3 out of 10. She still might have a bad night once every 1-2 weeks, but overall, it's like night and day compared to what we had before. My wife sleeps soundly on most nights. I can't begin to describe what a relief this has been.
We'll see how things go long term, but so far, we couldn't be happier.
That being said, my personal view is that using this for non-sleep purposes feels silly. I'm not going to use this to focus at work. But for sleep, it's been a huge help.
One other caveat, the thing is clunkier than most users today expect. The app is not great, and the device is less convenient than a Muse S, for instance. So I hope these things are improved. But all of this pales in comparison to the core benefit.
One last point, about the clinical studies - something I saw brought up by another reviewer. Here is a study on strong & positive PEMF effects on sleep from a group of scientists unaffiliated with NeoRhythm from about 20 years ago: https://pubmed.ncbi.nlm.nih.gov/10580711/.