If you already have a PS4, it's pretty useless IMO. I was at a PS VR demo and the rep even admitted this. It's funny that VR is one of the points they are pushing with the Pro, but the demo tour uses the normal PS4 and it works fine. And of course, 4K resolution means absolutely NOTHING if you're playing in VR.
I think the best thing to come out of the Pro is the corresponding PS4 price drop