I'm really surprised that only the A7 has phase detect AF. If you get the A7R, you are stuck with contrast detect AF only. That's a hell of a trade off to get more megapixels. With Sony's history of sub-par E mount lenses, they are going to have to demonstrate they can make lenses that are good enough for a 36mp sensor before I would buy one. I guess the folks that are planning to use Leica lenses with an adapter won't care about AF at all though...Could not care less about the AF. I have my 5D3 for such things.
The A7R will give me everything I've been missing with Canon. A big load of MPs and lots of dynamic range. I will be using it for traveling, studio work, landscapes, still life and architectural work. None of which requires state of the art AF.
Oh, and I do love that it's small.