Seems to me the Lilly is a better product and can do what this one does more or less, check it out, I love it, wish I had the money to get one. They are several discounted if you pre-order, around 600, then almost 1000 when they are officially on sale. https://www.youtube.com/watch?v=OWrApA8oRbI
Not sure if it's necessarily better. The Lilly also requires a tag to work, but it can only handle 20 minutes of battery with no way to insert a backup. This is relatively low-tech and seems to be capable of enhancing your existing hardware, rather than replacing it. That's a big win.
