In general, I've been pleased with this. Saw some improvement in my acne and perioral dermatitis with use.
However, after about eight months of infrequent usage (I'd tend to be really consistent for a week and then forget about it), my battery pack stopped functioning. I realized that you can plug the mask straight into the wall, so I didn't bother trying to troubleshoot or replace the charge pack. Big mistake!
When you're plugged directly into the wall, there is no built-in timer. You have to pay attention to your usage. Even before the pack broke, I would sometimes do two sessions a day or two sessions in a row and thought nothing of it. But one day while plugged into the wall, I forgot to set a timer, and probably spent nearly half an hour with the mask on (that's less than three sessions, for others who may be trying to push their limits). I took it off and went "ugh, where did that dirt come from?" When I tried to wash it off, I realized it was not dirt, but dark, dark pigmentation that had appeared on my cheeks.
It turns out, unbeknownst to me (I don't see this mentioned anywhere on the Omnilux site), blue LED light can cause hyperpigmentation in people with freckles or darker skin. As a woman with fair, freckled skin, these dark splotches, while not normal freckling, are not disfiguring. They blend in to my freckles well enough that most people won't notice them, they just throw off the balance of my face slightly. On a Fitzpatrick III or IV, I imagine it could…