The apartment was perfect for my family of 5. We had plenty of space. It was clean and comfortable and the air conditioning worked well-- essential for the summer! While you do have to walk up 3 flights of stairs, after we got our luggage up, no one thought it was a big deal. The apartment is in a non touristy residential area which we really liked. It is a lot more authentic than staying in the Ramblas area which I found to be tourist hell. There are lots, and I mean LOTS, of restaurants within a few blocks in which to eat and drink. That was really fun. The metro is also only a few blocks away, although we preferred to walk. We managed to walk everywhere except to Sagrada Familia and Parc Guell, but they are only a few stops away on the surprisingly very clean and air conditioned metro. Lastly, the hosts were very communicative and easy to coordinate with. Our flight didn't land until 11pm and sure enough, Guille was waiting for us at the apartment to get us settled. They also had several recommendations of places to visit and restaurants to eat at which we found helpful.
We would highly recommend.