The 50D has a more rugged semi-pro body with faster continuous shooting and higher maximum shutter speed. It also has AF micro adjustment. Would it take better pictures, probably not, but it *might* get shots that the cheaper model might miss if you shoot birds in flight or sports. As you surmise, it looks like the sensor is similar if not identical. If it was down to me, if you don't intend to shoot moving targets, I'd stick with what you've got, otherwise save up for the 7D.