After using Nervana for 5 days I should say it had an overall negative effect on me.
Pros
It relaxes fantastically, almost like diazepam.
Cons
It caused ear pain in left ear.
It caused heartburn.
On the fourth and fifth day it made me very sleepy throughout the day.
I think it is very powerful. Unfortunately there are no clinical trials done using this device or a similar device which stimulates the afferent nerve fibres going from the left ear to the brain. It definitely alters neurotransmitter levels. Since I am on anti depressants the device caused a kind of interaction. So I have stopped using it temporarily and will try after another 2 weeks.
Next time I plan to start and stick with 15 minute sessions (Only once per day before going to bed) and using low Intensity 3 to 5 settings and waveform A.
@perchance dreamer The device definitely helps with sleep. Will post after my second trial.