I REALLY wanted to like this camera enough to sell my 40D(mainly for weight).But it's IQ is frankly not as good as the 40D,and it's slightly noisier.I'm selling the Xsi.I'll try the next generation as I really want a smaller body.
Your opinion runs counter to the vast majority of professional, methodically-tested reviews published. Most say the XSi is slightly better in IQ, but to a degree that most users would never notice. The main cited advantages of the 40D are FPS, build, and controls (mainly the back dial). Some mention AF performance, but the differences seem to be minor. The XSi's sensor is pretty much universally recognized as being very capable in IQ. 







