We stayed for 1 week in Ana's flat. Just as described in the ad, the flat is in the heart of Gracia, a very lively quarter of Barcelona from which you can discover the city - either walking, cycling (there is a bike rental place like a few streets away) or using the metro (Diagonal station very close too).
Communication with Ana was easy - via mail and text message - and ensured a very smooth arrival at the flat.
The flat in itself has all that you can wish for to get a comfortable place to crash after a day full of visits: first it is very large (can definitely accommodate a family), on the first floor (so not a lot of pain climbing stairs....). It has a comfy bed, all mod cons in the kitchen. Bathroom is small but very well equipped. The only thing is that the flat lacks light, but since we only spent evenings and early mornings in it, this did not bother us.
I would definitely recommend staying in this flat.