I have been dancing Argentine Tango on and off for about 5 years. There are many styles and variations. There is some type of syllabus or base figures to use if you can ever find a good teacher that uses them. Most of the teachers we have had were spacy at best and always said there are no patterns--just dance and feel the music. Dance Vision has a syllabus and there are some solid basics to be taught in this dance. Arg. Tango has a passionate following. They go on Tango trips and etc., but there is not much competition--it's more of a social dance, but lots of demonstrations or showcases are done. Arg. Tango folks are somewhat narrow minded and look down on other dances and only dance Arg. Tango. I am still puzzled about Arg. Tango and how far I want to go with it. Wish I had a better teacher and more defined goals, a little more definition of the dance-- for improvement rather than just getting out and dancing socially.
International and American Tango are entirely different dances. Don't even know why they even call all these dances Tango.