Snakes win hands down... There is just so much diversity when it comes to our legless friends... Alot are specialized feeders and have some really cool ways of dispatching their prey... As far as "personalities" go, reptiles do not have them in the conventional way... Being active and searching their environment does not mean they have "personality"...
Dont get me wrong, I love leos but they are not very exciting or all that active... There is almost no challenge in keeping them or producing them in captivity... That is what seems to make them such a popular species to keep...
I think snakes are really beautiful, especially the greens and the oranges, but I have no interest in getting into rats and mice, even frozen, so leos it will be.