Well it's been a week and we had a few rainy days, the windshield had plenty of time to get dirty again, and Adam's Glass Cleaner performed equally as well as the Invisible Glass. The amount of waterspots after a week of weather abuse (daily driver is not garaged) was the same on both sides of the windshield, but far less than the amount on the other, untreated windows.
I've used many different glass cleaners and found Invisible Glass to be by far the best (before trying Adam's Glass Cleaner) so to say that Adam's and Stoner's are tied in this aspect is a compliment, I don't see how it would be possible for either product to have yielded any better results, given the testing situation. I'm sticking with Stoner's for now since I've got half a case left, but once that runs out I'll pick up a gallon of Glass Cleaner from Adam's.
Another awesome product, nice job