We visit Santa in Downtown Disney, they had a really nice set-up there. The CM's will put pictures on your Photopass, and they also will take pictures for you with your personal camera.
If you go on weekend/evening's it is a little busier, but the line moves fairly quickly. Not sure what time Santa gets his start during the day in Downtown Disney but if he is there during the daytime/weekdays the line would probably be shorter.
-mary