realized i didn't address the 2nd part of chingon's query.
good - easy, lots of mutant colors and patterns to choose from, convenient size, legal in most areas.
bad - starter snake, won't impress snake elites.
lampropeltis and pituophis are just about as easy, eurasian rat snakes too, but imo, they're usually assholes. most snakes of tropical origin are a little more fussy about enviro conditions, some of the australians not quite as much. some of the less commons, like lichanura/charina, sand boas & heterodon can also be easy, but most less-popular snakes are a little harder or require more specialized care at some life stage.