I purchased one of these recently and it failed within days of connecting it. Voipon replaced the item for me, and within minutes of connecting up the replacement, this device has also failed.
I may have been unlucky, but as a result of my experience so far, I can only give this device the minimum possible rating. I can only assume the device has a design flaw, or a bad batch has been distributed.
I will be replacing this second failed device with a similar product from a different manufacturer.