I decided it was time for a pro grade DSLR. Yes I have owned them in the past and never found their IQ as good as some of the lower bodies (1DsII vs 5D for example) but I want a solid camera, one I can use in the rain, one which will take some knocks. So, I invested in a 1D III, currently to be had for next to nothing on the used market.
I admit I have not had much time with it. The manual has been written by a geek, with no intention of ever taking a picture, probably in his lunch hour. The AF is complicated, yet somehow simple, which is why I can't work it out. It can focus on a blade of grass miles away, especially when you are trying to focus on a bird, feet away. I will stick at it.
I do like that I can use ISO 1600 without the need for extensive NR or PP, why Canon chose to add 18MP to the 7D is beyond me. Their claim is that wildlife togs have greater resolution to crop from is rubbish, cos then the noise is more obvious. For that, the 1DIII rocks. I can use ISO1600 now whereas on the 7D I only used ISO 800 at a push. I like that.
So far my only tests have been the wildlife near work, in my dinner hour. All taken with the 100-400, ISO 800.