We wanted another small dog for our Chihuahua to play with, since our Rottweiler is too big for her to be rambunctious with, so my wife picked a Papillon.
It's really interesting and different.
Energy like a mini-pincher might have, but moves more acrobatic-like. It's speedy - even as a little puppy. Very light-framed build for weight.
Slightly on the shy side, and cuddly.