I do dance to few Piazolla pieces if my instructor is not around. It is quite interesting when I asked my Argentine instructor if I could use Piazolla and she emphatically responded NO. I did not like the tone of her voice so I did not ask her to elaborate. I am not so sure if it is not danceable as far as she is concerned or she's just too conservative.
I was at a milonga and they played Adios Nonino which I don't feel comfortable about dancing to given its subject matter and Milonga Del Angel which is okay as slow pieces go