If you are referring to a BCI boa and a ball python then I would say temperament they are similar granted there's always the acception to the rule but both are very docile snakes. Boas seems more outgoing and inquisitive to me. THey just love to explore and hate to go back in their tub/tank when you are trying to put them away where balls are more shy at first and tend to take a while to feel comfortable when being handled. Other than thas theres arent any differences. unless your thinking breeding then pythons lay eggs and most boas give live birth I believe there are some sand boas that lay eggs if memory serves me correctly. Either way both great snakes for first snakes. Granted a boa will grow larger but not huge unless you get into the bcc's and other localities. If I missed anything anybody feel free to add.