This is a review by someone who's got 30 years of insomnia under control. Mostly.
SAD is a different thing and I can't speak for its victims, but if you've got insomnia, this can help... can not will because it'll only help with one aspect.
Before this light, I could lie awake till 5 am, finally doze off and then when the alarm went at 7, be so useless I could literally fall asleep halfway down the stairs to the kitchen... Had to keep alarms outside my bedroom door as if they were inside, I'd just slump and fall asleep on the floor/bed/wherever..
I still get insomnia (which the ****ing NHS will never, and I mean NEVER take seriously), but at least I can get up in the mornings... the gradual fade in of the light means I actually wake up, rather than dragging just that element of consciousness necessary for breaking a mechanical device out from under its stone, and going back to sleep/wandering off to make tea whilst feeling like a type B personality on a Valium overdose. Wake feeling ok, then 20 mins staring at it to get used to being awake. Then the day can start.
And if I get up better... there's a fairly good chance I'll get to sleep better. Not 100%, but 50% is pretty good.. after 30 years.
Essentially, GET IT.. if it's appropriate to your condition. Or if you just want to wake up without the screeching alarm.
right, back to bed, it's nearly 10 a.m.