There is a reason why the beauty snakes have so few breeders, demand is low, they have a bad personality rep and people get freaked out about the possible size and cage needed to house these guy. To a new own a possible 11' snake needing a 6x2x2 cages is quite intimidating as well as most personalities of these guys are pure evil.
I personally have a pair of blues and I am so far VERY pleased with how my male is turning out. He is a year old and still getting bluer everyday.
If you are really serious I would go to Ratsnake Foundation and get to reading all the articles they have (not many on the blues but more so on the beauty snake in general).
As for choosing between the two here is an example of a true blue beauites:
IMG_0103 by Mitsumike, on Flickr
I wish he was alittle more blue but I am very excited with his outcome. With the female i went a different route to see color transition from baby to adult.