Note that some bloodlines often share (or emphasize) certain traits, such as size, personality, willingness to feed (or not!) as hatchlings, etc. A good breeder should be able to tell which of his / her bloodlines will be the most suitable for you.
I usually steer beginners away from my okeetees, although they are generally beautiful, hardy, and great feeders. That is because they tend to be more nervous and take longer to settle down than my other bloodlines (most corn hatchlings are nervous at first, but these tend to be more so than other lines).
So you should ask each breeder as many questions as you need to about their bloodlines. That is one advantage of buying from a breeder instead of a pet shop or dealer - dealers will have no way to know about the history of the animal.