As a
GENERAL RULE cornsnakes are easier to feed than BP's. Some Balls will routinely go off feed and not eat for months! This drives keepers nuts! Corns are much more reliable when it comes to feeding.
As for docile behavior I would have to say that they are about equal. Its just that pythons are more laid back and mellow while cornsnakes are extremely active and "wiggly"! However I have come across both BPs and corns that were aggressive and would just as soon bite you as look at you. However this is not the norm. The problem with trying to catagorical describe a species is there are always going to be individuals that never read the manual!

A ball python will just hang out with you while a cornsnake requires that you pay active attention to what its doing, where its going, and just how much trouble is it fixing to get into!
Another key problem with BPs that you do not have with corns is humidity. Without proper humidity they have a tendency to have problem sheds. Though not a big problem it is something you have to deal with. I have never had such a problem with a cornsnake. They are native to this country and are not as picky about the humidity.
Cornsnakes will do just fine for years on adult mice but can eventually be fed with rat pups and eventually even small rats while Ball pythons are going to reach a size where it is more feasable to feed them on rats.
Both ball pythons and cornsnakes are great snakes and I keep both. The choice just depends on what you are going to be prepared to deal with.