We have bred both for some time now. Something else to consider when comparing the two.......corns generally breed like clockwork. If you are interested in going down that road in a few years you shouldn't have a problem getting eggs from corns. Some times I feel like breeding the balls is a type of long term scientific experiment. The corns go into brumation, come out a few months later (down time of no feeding bill) , eat, shed, and breed. I have also found that even the eggs of cornsnakes are more forgiving of temp gradient etc.
Ball pythons for whatever reason have always been my fav., but you can't beat the color options on corns. We started out breeding around 10, now we have 40 adults and 40 hold back babies. And if you like purple the lav. bloods are starting to come down to a good price.....