I've had both before and currently have Bree, so I'd have to say go with her! Though that's pretty biased because she was one of my first villagers ever (back on WW!) and she's one of my favorites! ^^
Call me crazy, but I'm going with Bree. One of the reasons is that as one of my original villagers, I have a major soft spot for her. Not to mention, she's a cute little mouse. How could you not love a cute little mouse?
I would recommend Olivia! I had this villager before and she has that "snooty" look if you will (I will always enjoy her makeup and original clothes). I also take a liking to cat villagers as well