Ours took 9 months of careful training to be housebroken. She'll come on a whistle, but that took a long time, too.
She's good with kids, and she housebroke our mastiff when he was a baby, other than that, really really dumb. But she's like a little black shadow...
OH! I forgot--she's a great mouser! When we got this house a year ago, it had mice. She has a bell on her collar, so it wasn't easy, but she got three of them. I think that's what they were bred for, originally (about 400 years ago in Germany).
Never knew rodent control was a fringe benefit of MinPins.