I guess having additional powder measures would be easier, but I also change between calibers without much problem.
Not sure that the 10 minutes "larry" quoted is accurate, though. Not only do you have to change the powder measure from one die set to the other, you're probably going to have to change between the small and large measuring bar. Changing to different sized primers also is time consuming.
I'm thinkin' 15-20 minutes is more like it...