David and his wife Laura were very nice and easy to contact. The location of the David's place is perfect: 15 minutes to Sagrada Familia by walking (almost the same distance to Park Guel). The neighbourhood is friendly, the local market with fresh goods is just the next door.
However, we'd like to point out some inconvinieces from our point of view. First, it would be great if there was a kettle in the apartment. Also, we were kindly provided by the baby cot, but not with the extra bedsheet and pillow (we had to use our towel to cover the bed). Besides, the cutlery in the kitchen was not clean, but maybe that's the fault of the previous visitours. Finally, the beds were short: for tall people it can be problematic to sleep.
On the whole, we quite enjoyed our stay at David's place! Thanks for hospitality and help.
Note for those who travel by car: we didn't expect such problems with parking in Barcelona, so bare in mind that it is very hard to park the car anywhere nearby.