Mireya's ground floor, straight off the street, apartment is compact but well equipped, and immaculately clean. We really enjoyed our 5 night stay there. There is a small patio which is lovely to relax in at the end of the day (with a glass of wine, in my case).
Mireya has thoughtfully created books of information about what to do and where to go in Barcelona, and especially about the local area in terms of markets, shops, and places to eat (which was extremely useful).
She also has a range of guide books for guests to borrow.
Things outside Mireya's control are the mopeds and motorbikes which whizz along the street outside quite late at night, and quite early in the morning, and the nightly street cleaning crews (not every night). If you are a light sleeper, you might like to bring earplugs.
The local market and supermarket are less than 5 minutes walk and are both really good. The Metro is also only 5 minutes walk from the apartment, as are several good places to eat.