Enid at guess I'd say amateurs, but no way of knowing for sure. There are a few AT festivals in Buenos Aires and during those the streets are filled with dancers, I'd assume most of them are amateur but a few will be Pros.
Quite often the Pros look a bit "too polished", these dances are quite earthy and should look natural - more a conversation between two people than a fixed routine.
MrsJamin, I know what you mean, Joanna Leunis is a perfect example of the way changes in speed can be used without losing the rhythm of the dance.