I bought a bottle of
Adams' Carpet & Upholstery Cleaner a long time ago, but finally got around to using it this weekend - it's good stuff.
I've had a couple food stains on my passenger seat for probably 2 years now (2004 MCS with Space Cloth) and Adam's took 'em out easily: Just sprayed it on the stains, rubbed it in with my fingers, and then blotted off the excess with a detailing MF.
The only problem was that when it removed the stains it showed me how dirty my seats were! I had to use it all over both seats to make them evenly clean. That didn't take long at all, though. I just had to spray them a couple times to make sure the cleaning was consistent.
I haven't used other cleaners like this before, but I can't imagine there would be something easier to use.