Neither. A used 6d would be the much better choice.
Both the cameras you are asking about are geared toward sports and wildlife shooting. The sensor in the 6d is full frame which allows you a wider angle of view with the same lens as the other two. If the 6d is too expensive even used, then you might as well save a few more dollars and just buy a 60d. The advantages of the two cameras you are asking about are not aimed at your type of use.
As for the best choice between the 70d and the 7d original, the 70d would probably be a slightly better choice due to its better low light performance for real estate use.