of the new names that have been mentioned i have to second Luana... wow cant believe i forgot her! as well as August, her ass is pretty good as well. Rachel starr has a pretty perfect ass, more 'normal' sized though, an ass with more play like alexis texas is what i prefer though.
sara jay has a nice big one that i like, but to be "best" it does not have enough shape, just big and wide.
nobody has mentioned Mia Bangg either. also Ayana angel is no joke. think with my previous post that rounds out my top 10!
oh and i almost forgot the newest youtube queen peachtree! she is a new fav of mine!
nobody is with me on Scarlett from assparade though? she has done 4 scenes with them and nowhere else that i am aware of. her ass is unparalleled.