Great location in San Telmo. Check in was easy, co-host Guillermo texted a few days before arrival to coordinate and was at the apartment when we arrived. It's an old building, apartment is on the second floor so there are stairs to climb. Furnished well, breezy feel to it. The small kitchen was well-appointed (fridge, microwave, stove, oven, coffee maker, implements, etc) and basics (coffee, tea, salt, oil, etc) provided. Hot water was "instant on" which was nice for the bathroom.
Guillermo's restaurant recommendations were great. He texted a few times during our stay to make sure all was well. We had a late flight out, Guillermo allowed late checkout (5pm) which really helped. He wasn't able to be there for checkout, which was not a problem; he arranged for a taxi to pick us up for the airport.
We'd stay there again in a second.