I recently upgraded this past weekend to a 1d series body and all I can say is wow! I haven't had a lot of time to get use to it yet, but what time I have spent using it has been really enjoyable. I really didn't think it would be as big of a learning experience coming from a 7d, but was I wrong. It has a lot more custom settings and functions than I'm use to. The body itself feels better and more balanced in the hand than the 7d with a grip attached. The controls are a little different yet most are the same. But what really has got my attention more than anything else is the image quality @ high ISO and low light situations, not that the 7d is a slouch. The colors seems smoother and more vibrant. I resreached the differences between the 1D3 and the 7d for months before my purchase and I'm happy to say I'm glad I made the move so far. The 7d is a great camera, but to me the 1D3 is all that and much more, maybe a placebo effect, but I like it.