Some of the most successful/fastest-growing Appleseed states are states like California, New York and Illinois. They also happen to be the big population centers.
I think it reflects the desire by residents of those states to have more opportunities to use/practice with their firearms.
As a former NY-er, born and raised on Long Island, I can see and understand why there'd be a pent-up demand for something like Applseed.
HERE'S a link with more info about the Appleseed 300. Impressive picture of the shooting line.