My best mate Ben was the Hammond player in my band many moons ago. There was a rival band at the time whose keyboard player Tim also had a Hammond, albeit a smaller model. I asked Ben what the difference was between them, and he explained that when Rick Wakeman was touring with Yes, he had one of each as part of his stage setup:
"He used the one like mine for playing the songs, and the one like Tim's for sticking big knives into."