I had the 40D - great camera and went to the 7D2 - LOVED it HUGE upgrade - IMO amazing camera.
I played with my friends 6D and liked the 7D2 MUCH better for features I wanted and for general feel (I also shoot mainly sports and pets).
I wanted better low light performance and went to the 5D4 - love it - but miss the faster frames per second - can't afford the 1DX2 (yet). So, yeah, as others have mentioned, the 5D3 would also be a serious contender.


