The 70D is a crop sensor camera with 20.2 MP and a DIGIC 5+ processor. The 6D is a full frame sensor camera with 20.2 MP and a DIGIC 5+ processor. The 70D seems to shoot more frames per second on photos than the 6D, but I think these two cameras are very similar - with the exception being the sensor of course. If you consider going full frame an upgrade, then it's probably an upgrade.