Although I have never owned fattys I do own two leopard gecko and can tell you right now that leos are a bundle of fun. I really cant tell you everything they do or anything, there just so much fun and definitely very good for beginners and experts alike. They're possibly the best pet for someone who likes to go on vacation as they can go 3-4 weeks maybe more without eating.You would have to try to kill them. I'm not sure but I think that fattys are not as widespread just because leos were domesticated before them and have many more colour morphs. I think that fattys are pretty much the same as leos except with different colours.