I'm looking at either the 6D or the 70D when it comes out.
Canon made the choice between the 70D and 6D quite difficult, IMO.
Without a doubt, the 70D is the more well-rounded and versatile camera.
The 6D is a one trick pony: it has a FF sensor and ... that's it.
Of course the 6D will be the better camera in terms of image quality.
Canon stated themselves that at the RAW level, the 70D ISO performance will be 'on par' with that of the 60D.
The 6D has about a ~2 ISO stops advantage over the 60D, which it will obviously keep over the 70D as well.
So, if you decide to go with the 6D, you are obviously going to get better image quality.
But this will cost you more - and at the same time you'll be losing some fun and useful features.
Like I said, Canon made this a difficult choice.
Good luck with your decision.