This was our first time with airbnb and we're happy we airbnb'ed. We (I, my wife and our 8 year old daughter) stayed at Laia's apartment for 5 days. The apartment has pretty much everything that a family requires. There's a full kitchen if you want to cook, a jacuzzi to relax after a tiring day and all other facilities/features as described. There were some essentials already available in the apartment so that we didn't have to go around looking for a supermarket immediately on arrival. The neighbourhood is excellent too and the apartment is located minutes away from Las Ramblas and Pl. Catalunya. There are many supermarkets around too.
Laia is super responsive. She helped us with all the information as we were planning out trip and while we were there.
Overall, we had a great time. If we return to Barcelona, this is where we'll stay again.