I'd go corn over ball python. You seem to be interested in a more active snake, and from what i've seen, corns are MUCH more active than bp's. However, I have seen one bp that was just all over the place... but thats one out of dozens of different bp's that i've seen.
Also, why don't you look into a texas baridi? These guys are gonna be about the same size (4-6 feet), they are ugly ducklings but they are STUNNING as adults. And what I love, they got that texas attitude, lol. Mine's never bit or struck at me (except during feeding time through the glass lol. After she's had one mouse if i'm standing close she'll strike at anything moving. I call it PMS... post mouse syndrome)
The main reason I would suggest a corn or bairdi over a bp is, besides the awesome coloration, you get a lot less stress when feeding. I've heard of plenty of bp's that don't like to eat.
Either way you go, make sure you get a captive bred.
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Chondros and colubrids... my 2 favorite types of snakes!
"Life is hard. Life is harder if you're stupid." - John Wayne