My boy yorkie was WAAAAAAAAAAAY more easy to train than my girl. Hobbs will run to the door when he needs to go outside. Hootie knows she is not supposed to potty inside, but she won't let me know when she needs to go outside. And if I don't take her outside and she needs to go, she'll go in the house. Ugh.
I think my boy was easier to train because my boy is more eager to please than my girl. My girl is more independant and could really care less if I'm happy with her or not.
My boy is very sensitive and gets his feelings hurt easily when I am mad at him. This makes him WANT to please me, thus he was easier to potty train.