Pretty good diffuser, but felt mislead by the "metal" touch name, thinking the exterior would be made out of metal, but no, it's merely plastic (at least it's bpa-free).
Cons: I find the metal touch on/off switch quite annoying, as I always trigger it to turn on just as I'm removing the top to refill. Surprised no one else found this annoying, as I'd prefer an actual button.
I have another diffuser which has a timer option and custom light selection. For this price, I would have expected similar options and would've traded these for the 'metal' touch.
Pros: indeed, it's very quiet, and the longest lasting diffuser I've encountered. The no light option is nice too.