I think that one of the biggest advantages of Colubrids (Kings, Milks, Corns etc) are their size. They don't need the space that a big snake does and they can be handled very easily once they get used to it. Also smaller snakes will consume less food than a larger snake.
Lets see...Colubrids come in a wide array of colors and patters. They might be more active than larger snakes (???) Therefore making them more fun to watch. You most likely won't have the police/fire dept/animal control at your door if your snake escapes. Big snakes seem to end up on the news when they escape.
Keep doing research and you will "fall in love" with the kind of snake that is perfect for you.