I am using a 70D right now and am starting to get more and more work in photography, so it's time for an upgrade soon. I would obviously like to go full frame, but I am not sure what I really want or need. I see the differences in specs, but, that doesn't mean anything to me until I actually go out and shoot with the cameras. So, what I want to know is, in your opinion, what's the better option. I don't have the budget for a Mk IV or V, and I don't care about size. I am mostly shooting portraits, landscapes, concept, and night photography. Will I be able to do what I want with a 6D without splashing cash for a 5D? Is there a significant difference between a 5D II and III besides the dual memory card slots? Thanks for the advice, guys.