I forgot to say - As they grow, most prairie kings get brownish gray. Not attractive to many people. Look up some pics of adults and see what I mean. They are nowhere close to corns in beauty.
Their closely related cousins, the mmole kings are slightly more attractive, but again, while pretty in their own way, not eye-catching when compared to other captive snakes.
Also, calligasters are fairly flighty, musky and poopy and don't tend to calm down for a long while (At least all the ones I've dealt with were).