It's great, haven't had a problem with it yet. I've tried other brands of this same concept but they fall apart pretty easily. I've had this one now for a few months, and besides the point that if its dark it doesnt have a little light in it, its perfect. I wear it 24-7.
I really didn't want to buy it knowing its got some ionization stuff going on, but it hasnt gotten in the way yet. So it's worth it to me.
I will be buying more of these, but I will be trying the smaller design next, this one was a little more bulky then I expected.