Has anybody tried Cuppow?

Just wondering if anybody has tried this http://www.cuppow.com/. I've seen pictures of Cuppow all over Pinterest and just wondering if it works good? It's right up our alley looks like you turn a small mason jar into a reusable drink cup by purchasing their BPA free lid for $7.99, Karen and love this kind of stuff, if there is anyway to reuse or reduce waste going into the landfills then we are all for it. I'd like to find out more about it before I say Yay or Nay. Anybody out there purchased one of these yet?