The 50d is such a great camera. It's super easy to use and Canon does a great job of making it easy to transition to from one canon to the next. On the dial you have your basic camera modes in auto and manual but Canon has added three new dials, CA, C1, and C2. I haven't dabbled yet in CA but C1 and C2 allow you to save custom settings. So if I know that when I shoot in studio I need my camera set a certain way I can just save those settings on C1 and turn my dial to C1 every time I have a studio session. Aside from the obvious boost in image quality from my rebel the 50d just feels like a better camera. My rebel could be described as dinky and puny in comparison. The 50d is noticeably larger, more powerful, and it makes a really beautiful shutter sound. I seriously love that sound.
As far as image quality goes, click on the photo above and view it large to see how grain looks. My xti has noticeable grain if viewed large and the light is not evenly distributed, it's a darker photo all around. You can also see a noticeable difference in white balance. Overall, I am so so so glad I upgraded. Oh, and in case your wondering (Mom and Dad) SOOC means straight out of camera, no editing or enhancements.