They used to provide a lot of Brazillian staff a few years ago not sure if they still do.
The guy who runs it organized a job for me a few years back but because there was no profit in it for him due to client day rate and my expectations he just passed me the details and allowed me to negotiate with the client direct.
Therefore I think they seem ok.
Also worked with a guy from Austrailia a couple or four years years ago who was through them and he had only good things to say about them.