I'll also have to disagree with the claim that corns will bite more than ball pythons. Rarely, hatchlings will be a little nippy (and you can hardly feel it when the do bite). But they grow up and calm down quickly. I haven't been bitten by a corn older than a couple months. Even if they -do- bite more often, their heads are so small when that's most likely to happen that it's not really important. I think it's kind of funny when an 11 inch, 8 gram snake tries to bite me.
In my experience, ball pythons and most other boas and pythons generally have a more aggressive feeding response than corn snakes. If your hand smells like a mouse, be careful. I've been bit twice (my fault) by my ball python because I forgot about her feeding response. My corns don't care one bit if my hands smell like mice. They've never made a feeding strike at my fingers. (but then again, they usually don't strike at anything. They're lazy eaters, usually nudging the mouse before opening their mouth and eating it. Sometimes they constrict, but don't seem to 'strike' in they way that my ball python does)
Corn snakes are a bit easier on the maintenence side. Humidity has never been a problem with mine, no humid hides/misting/what-have-you to increase the humidity - the house humidity is fine for them. Also, they don't need temperatures as high as ball pythons - 84 on the warm side will suffice, with room temp on the other side.
Hatchling corns are flighty, but they do calm down with age. My 2 year old corns are content enough that I can sit down and do something with them on me, with occasional checking up to make sure they're not going away.
Also, you have such a wide variety of colors available, and they won't require you getting a second mortgage to pay for them. You can find nearly every corn morph is under $100 - with many for $50-30 and some even less.
Ball pythons are much thicker than a corn snake, so they look a lot bigger, even though they get to around the same lengths. They don't squirm around as hatchlings. They do need slighly higher temps and humidity than a corn, but nothing too extreme.
I think either one is a good choice. It depends on what you're looking for. If you can't choose, get both
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-audri
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