Kenyan's get Fatter, Rosy's stay Thinner, both about Equally as common but I would recommend a Rosy Boa over a Kenyan for you, Kenyans are definitely more Snappy as babies, Rosy's are generally more docile. Most Kenyans grow out of Snappiness as adults but I would just pick a Rosy,they both require very similar care. If you have anymore questions feel free to ask.