I very much recommend staying with Carolina in her wonderful and very central room in the heart of San Telmo.
The room is very cozy and nice, and it was great to have my own bathroom plus a spacious roof terrace.
Carolina is a great host. She offered to show me around, recommended theaters and films ... And was always helpful regarding any question.
If you're planning a longer stay in Buenos Aires, i would definitely recommend Carolina as a roommate and her house as a great starting point to explore the city!