Yes, yorkies are great companions, but they are also a lot of work. Before getting one, I highly recommend you research the breed. As another posted, if you like privacy when you go to the bathroom, forget it!
Also note that if you're gone from home a lot and don't have the luxury of bringing your baby with you, it will be hard on the pup. They do not like being alone, and they really don't like being away from their "person". This means that even though someone else may be home, they much prefer it were you!
I can go upstairs for two minutes, but by the way Addie acts when I come back downstairs, you'd think I'd been gone for a week!