Audi announced that it is planning on building and all electric SUV to compete against the Model X. They will be about three years behind the Model X.
My take on it is great! Elon open sourced the Tesla's patents because he wants some serious competition. The more the merrier.
But at the same time, I am very skeptical that the Audi will be serious competition, unless they buy into Tesla's Supercharger infrastructure. As a current Model S 85D owner, I would not have purchased this vehicle without the Supercharger network.
On the flip side Audi may raise the bar when it comes to comfort and luxury. The Model S, and I assume Model X, have a elegant but spartan interior with a minimalistic flavor. If the Audi interior is on par with their ICE variants, I think they will provide serious competition.
I'm very happy with my S85D, but may trade it in on a X85D in the future. However, I'm not doing to put a deposit down until I can test drive one.