Claudio's apartment is in a residential area, but there is anything you need is just a few steps away. The apartment itself has a magnificent and quite secluded roof terrace with excellent views across the city and catches the sun beautifully for much of the day. A little care should be taken when climbing the stairway to the terrace with drinks in hand.
We found the apartment was plenty spacious enough and quiet, with very little traffic noise.
Claudio provided us with details of several places to eat both locally and within the centre. As the Gracia area is predominantly residential, most of the restaurants were very reasonably priced and favoured by local residents, and all were very accommodating.
The Verdeguer Metro station is a few blocks away, and we travelled easily from the airport using a T10 ticket with only a single change from R2 mainline to metro (can do this either at Sants-Estacio or Passeig de Gracia).
Claudio was also very helpful in providing details for some of our intended visits and was available if we needed assistance. He is an extremely generaous and accommodating host.