@ragnav--I have been using my V633 for around two years now, in conjunction with the V810. It has helped some symptoms--I had an ugly knot of varicose veins below my right knee (this never caused any problems, mind you) and this has been significantly smoothed out. My nasal responsiveness to allergens has been radically lowered. I am now again using the two together to try to improve my hearing loss (I am 84, so this is not a rare symptom!) and tinnitus, and it seems to be having some slight positive effect, so will continue. I switch ears at 1/2 time, so that each ear receives the same amount of light at each session. My BP has also lowered a bit, and I have fewer and less intense BP spikes, I would say, though I cannot for sure say that the 633 has been responsible for this. I have a friend who has had serious Deep Vein Thrombosis, and she has found that if she occasionally goes for a walk without her usual compression stocking, she comes back with no significant swelling or pain--definitely a real change. The 633 is the only unit she uses. All in all, I think it is a useful if unspectacular unit. I have met a dedicated fan of the 655, who told me that several years ago she was threatened with amputation of her left hand due to PAD, and that the 655 saved her from that. I understand--and share--your reluctance to buy the 655, but it seems that given the degree of convergence built into the diode unit, there is very little danger. But I share your hesitation about the laser .