Yes I have and yes I have.
I still have the 40D and use it as my second string but the 7D is a much superior tool.
Still use my 40d for landscapes but the AF on the 7D is a big step up.
I have found the af, image quality and high iso usability much better on the 7d. It's a much better camera.
Also, whats this 100% viewfinder? i dont get it? my 400d as a 100% viewfinder?