I was waiting for the 70D for a long time, until I decided to buy the 6D three months ago.
Previously I've used a XTi with EF-S 10-22 and 17-55 f2.8, plus 70-200 f4 L IS, and I really wanted a 7D or 60D replacement (so I could stay with both EF-S lenses), but I must say that I do not regret buying the 6D. As a matter of fact, every time I use high ISO I know that I'm using the best available.
Also, I don't know if I'm luck, but my EF 24-105 f4 L nails focus 99% of the time, even in low light conditions with the outer points (but I don't do sports, so I cannot say about tracking). It's night and day compared with my old XTi - image quality, focus accuracy of all points - it gets the picture I need every time I press the button.
I only miss the 10-22.
Had not experimented, would I buy the 6D today with the 70D available? Probably not, since I would save some money and also would not need to sell my lenses to go FF (I'm buying a condo, everything counts). Having experimented the 6D, would I change it for the 70D today because of its specs? Nope.
I think the only 70D feature I would like to see on the 6D is the new focus on video. That is really cool.