I switched from 7D to 1DMKIII. MKIII has 7D beat just about every place you can think of. Couple of advantages that Team mentions but the MarkIII is deadly accurate, has more focal points and if you use read the manual and try to learn as much about these custom functions and more importantly, when to use them and change them around for different circumstances, my opinion is that it leave the 7D in the Rear view mirror. Best decision we made was jumping on a 1 series and dropping the 7D. Liked the 7D, love the Mark3.
Here is what I did with my 7D.
I sought out those who have used it successfully in different venues.
The guys who used it for Auto Racing with excellent results.
The guys who used it for Birds In Flight with excellent results.
The guys who used it for Portrait work with excellent results.
I asked them all about the various settings they used and came up with a cheat sheet of sorts. I put those setting for the three main areas in C1, C2, C3 and I love my 7D.
I have been extremely happy with the 7D .... even happier with it than with my 5D2. I still do not know why I bought that 5D2.