That's a tough decision lol. I love both morphs but as far as color changes go, I think that clowns hold their color a little better as they mature. But both are amazing morphs and have tons of possibilities.
Clown for sure! Lol My project is to produce killer clowns and a new clown morph. Yes, color's do change on clowns.
I don't know much about pieds but I don't think they change that much as they mature because how they came about in the first place. Why not buy both?
Well if you have the money for both of course i would say to get both lol :p
But if you had to pick one i would say go clown. Pieds have dropped drastically in price and it seems like a lot of ppl have one and are working with them. Clowns are definetly still more rare and theres more opurtunity to produce a new morph. This is all just my opinion from what i have observed on here, kingsnake, and at expos. Now i can get a male pied for $550-650 plus 2 females het pied for $200-300ish dollars each. So for $1000 you can set yourself up with a pied breeding project. Clown males are like $1200 by themselves. Id go with a clown project