Canon EOS 450D (EOS Digital Rebel XSi / EOS Kiss X2) review

Overexposes--anyone else have this issue? I "downgraded" from a Canon 40d with Sigma 18-50mm f2.8 Macro (highly recommended if you do not need IS and like continous f2.8) due to weight. The 450d/Xsi with the 18-55mm IS kit lens is outstanding value (475 pounds with 18-55mm IS kit lens--almost same price as in USA) and the weight difference has cured my neck and shoulder pain! The 450d/Xsi is easier to use in my opinion--the absence of the extra LCD screen on top is not an issue as the large 3 inch screen on the back is easier to use. It is also easier to adjust exposure compensation on the 450d compared with the 40d. As I rarely use continuous shooting I do not miss my 40d in any respect although it did "feel" more like my high end film SLRs of old. The kit lens is stunning--unbelievably good throughout the range. Unless you need f2.8 I cannot see any reason to upgrade. I also use the excellent 70-300mm Canon IS and the equally excellent Canon 10-22mm. The 500d with its 15MP may face the same issues as the 50d compared with the 40d--why bother?

Problems:

Yes. My 450d has a very strong trendency to overexpose whenever there is a particulalry dark object somewhere in the frame. My 40d rarely overexposed and I understand they have indentical metering systems. I therefore tend to use the easy to access +/- button and cut back 1/3rd or 2/3rds of a stop but this sometimes causes underexposure. Anyone else had this problem with their 450d?