I don't use the dealer because by the time I get there and back, I will have lost over an hour and a half, if not more.
With the Fumoto, I can change oil, and rotate tires in under 40 minutes. Most of that time is letting the oil drain anyway. It has nothing to do with money for me, more for my time savings. I usually bang it out on a Saturday at like 7am. Eat breakfast with the kids by 8.