I moved from the 7D to the 5D III over the Christmas holidays and I haven't looked back. The pictures the 5D has produced straight from the camera are stunning.
In addition to that, I shoot mostly landscapes, so the "loss in reach" was actually beneficial to me. Seeing how wide my 24-105 can actually go-- and being able to use my 14L to the fullest-- made the jump worth it, no doubt.
The only real loss I see form the 7D is the frames per second, but at 6fps or so, the 5D is adequate for me.
Otherwise, besides the general image quality of the 5D III, I was really impressed by the "silent shutter" feature. I hadn't heard a lot about it in my research (which is why it was a surprise), but I actually found it more useful than you'd think.
Otherwise, if you've done your research, you know what you're getting. If you love photography and you have the money, go for it. No question.