I love 5d2 - love the files and what you can do to em in post... But if 1ds3 is close in iq I'd go for it working professionally with a 5d2 would bug me I think as it reallly doesn't perform well with off centre focus points when in a hurry to get the shot. And shooting off centre is important and when going fast as focus recompose can miss shots so easily - ESP wedding where it's a look or an expression you want... Doesn't solve your video itch but it gives you rugged one series bodies that behave the same as your mk three... Hard choice