We enjoyed our stay at Marta's. The shower was especially fabulous - spa-esque really - the bed and room were comfy, the location suited us too: in a quiet residential neighbourhood, out of the centre but surrounded by excellent small tapas bars etc. Marta was friendly and helpful as a host.
I must add that some of the below reviews seem a little unfair. The ad makes clear that you are staying in Marta's home, and this sort of experience is what we like best about Airbnb. As someone's guest you expect to abide by their rules, and Marta's were absolutely reasonable - looking after her wooden furnishings, turning off unused lights, and locking the front door. To do so is to respect your host's personal space, and we prefer to be told this stuff upfront than to unwittingly cause upset. If you're looking for your own self-contained and fully private accommodation, this wouldn't suit you. But if you are comfortable in someone's home, this is a really lovely stay.