I went in 2006 and again in 2012 so my info is pretty dated. Both times for free range stag. The hunt in '06 was with Algar in Patagonia and on horseback (you can also do it in trucks) and was one of the best hunts my wife and I have ever done. the area sort of reminded me of Wyoming.
The other hunt was in La Pampa. Also a fun hunt but more heavily forested and was similar to mopane in Africa.