I can only think of pros for having a yorkie. Mine is so lovable and cuddly. I love that he will curl up on my lap and go to sleep. He loves everyone he meets. Such a sweetie. I have been around many different breeds, and the yorkie is definetly the BEST!
I have read that yorkies were hard to house train, but it only took me a few weeks to house train Louis, and it was litteraly during a blizzard.