This was our first foray into airbnb and we had a fantastic experience.
The apartment was better than described, and our host was excellent in every respect. Our host even stocked the fridge with basics so we didn't have to worry on our first evening having to look for a supermarket. We shouldn't have worried though as there are supermarkets just along the street.
The location was ideal for both the beach and city, with public transport (bus and tram) only yards away.
And we would recommend Valencia as a destination. The city is beautiful with huge history, there are many and varied attractions to keep everyone busy, and the locals are friendly, relaxed and helpful. We found plenty to keep us occupied for 6 days, highlights included the city walking tour, the science, arts and aquarium complex, biopark and beach area.
All in all a great holiday experience.