I'm surprised to see such a large percentage of people, vote for the 6D over the now-discounted 5DII.
I'm a APS-C shooter looking to move to FF... after seeing the shape of things, I snapped up a $2600 5D2 kit from amazon, to replace my 7D and 17-55. I figure that means I paid $1700 or so for the 5D2 itself.
The biggest things that I didn't like were the only-marginal improvements in AF, the need to make part of the body plastic for the wifi/GPS, making it less dust/weatherproof, and the slower, laggier, less durable shutter.
As a bonus, my 7D used CF, so I don't need to re-buy memory cards.