*shrug* I find the color balance between the 3 to be very underwhelming myself, I notice when people turn real people in to ponies they have a bad habit of making their main fur colors brown, pink, or yellow. I like the person's designs, sure, but as a group they don't balance out color-wise and they all wind up looking too similar. Doctor is brown and brown. Rory is brown and brown. Amy is yellow and red. I like to try and add in the colors the characters are themed with, what they tend to wear or what colors promote certain personalities, and I like them to look more like ponies and less like people turned pony.