Not only do I store my setups on the CF card, but I purchase the VEx expansions. I literally have hundreds of quality kits to choose from. I have two TD-20 modules that I use in 3 different configurations. For my last show with the Zendrum, I used my kit editor to build a collection of the kits I was going to use in the order they were needed. I saved this to my CF and loaded up my TD-20. Voila, I just pushed the up button on the Zendrum after every song and there I was.
Now, when I use the TD-20 with my regular kit, or my Super Kit (The Mondor) I just load the settings for those.
50 seems like a lot of slots till you start getting custom ones. Then you want as much storage as possible.
Plus the CF stores all your pad settings as well. I could factory reset my module, pop in the CF card and away I could go.