Argentina is massive, and getting around the country requires money (air) or time (road). Hence we only managed to visit Buenos Aires, which had enough to keep me busy for a week.
Most important tip for Buenos Aires is to stay at San Telmo! So many good restaurants, parillas, markets, milongas, tango shows were within walking distance, and we never needed to cab home after a late night. We slept at Hostel Carlos Gardel which was right opposite San Telmo Mercado, and we always popped by to buy cheap cuts of meat fresh from the butcher. We were also hooked on the excellent coffee from Coffee Town. On Sundays the Mercado is at the midpoint of a full blown antiques market, consisting of gaucho goods to silverware, handmade items and more.
Most Milongas start of with a class at a small fee, and they are normally suitable for English speaking beginners. The teachers we encountered were very forgiving of our amateur Spanish and tango skills to match. Our favourite Milonga was La Maldita Milonga at Perú 571, because the live orchestra Orquesta Típica El Afronte was simply mind blowing and stirred up such an unforgettable atmosphere. There was also a demonstration by professional Tangueras that showcased quicksteps and elegance. Another memorable one was at Manzana des luces, a heritage art museum where we had our lessons in between art collections, and the Milonga was at a romantic outdoor courtyard where couples twirled under the stars and soft lighting. This website is great if you want to go to a Milonga in Buenos Aires. I highly recommend not going to Tango shows or sidewalk performances, but to choose to experience a Milonga instead. It is much more soulful, emotive and authentic, and consist of real people dancing for passion instead of for tips or as a job.
The best Parilla we went to was La Brigada, which did not look like much from the outside but was packed to the brim once you stepped into their multi-story building. While waiting for food my partner was fully occupied with their displays of football jerseys from different eras, and when the meat came it was easily cut with a spoon by the waiter. Amazing quality and so juicy! Alternatively go to Nuestra Parrilla for cheap Choripan and steaks after drinks/dancing. The small shack is normally crowded with locals at night and it is a great place to meet people. Most local places close for siesta from 3-6pm, Merienda is at 6pm and dinner places only open at 8pm. Its an awesome concept that allows people to stay out later at night, but we were hungry for dinner way too early and defied our hostel restricted cooking times (8pm-10pm), angering the old lady living there for some reason.
The pretty street in La Boca is not the best thing in Buenos Aires. It feels forced and pretentiously touristy, and even the Tango performances are emotionless. Go if you have 1 hour to spare.
On our last day we went for a Ballet at Teatro Colon at a steal of USD$6 for a ticket which was cheaper than the theater tour. However our view was so restricted and my neck was cramping after straining for 2hrs. Definitely getting better seats next time!