I will try to be a reliable source--I have now had a good deal of experience with the 810, and also the MED-X units, and a little with the Vielight 633. The 810 has definitely improved my sleep, to a significant though not revolutionary level. It has also improved my overall mood, has slightly improved my aged hearing, and reduced my tinnitus a bit. I also walk with more confidence over rough rocky ground. I would say I am very pleased with the unit overall, and plan to continue indefinitely, probably with periodic breaks.
The 633, aimed differently, has been helping a friend of mine, same age-82--in some quite specific ways; she has no neurological problems, but has deep vein problems in one calf, and it has helped there very noticeably, and has also helped her sleep. I tried it, and it seemed to induce a kind of excitation that was not pleasant. I suspect that for us ME types the 810 is the one choose, though Lew Lim says that a couple of people with ME had some success with the 655, the laser model--but, being a laser, it is capable of damaging eyes if used carelessly, so I am steering clear. I do intend to find out more about their experience if I can.
Lew has now produced the Vielight Neuro, which consists of a more powerful version of the 810 (they use the same basic parameters, but are not interchangeable), together with a four capsule head set. Looks very interesting, but expensive, and not yet really tested--brand new. Aimed in the first place at Alzheimer's.
The MED-X units are much more powerful, and need to be programmed--very flexible, but designed to be programmed by professional health care providers before being put into the hands of patients.
All of these units aim to interact with elements in the cells, primarily mitochondria, where they promote the chain that produces ATP, but in the process also increase ROS and also, one hopes, the glutathione and other antioxidants that combat the ROS. There are a couple of studies on a mouse model of MS, the disease closest to ours, that indicate that one needs to go slow and low in dosing, and to take periodic breaks. But there have as yet been no studies on many of the major autoimmune diseases like Lupus or Sjogrens -or us--unless I have missed some, quite possible ,but I have looked. The 633 seemed to produce more ROS than ATP--at least that is my subjective impression. The 810 is a calmer but quietly effective unit--don't expect quick miracles, but I think it can do good things for us. Hope this helps a bit.