Garikoitz is a very good host. The apartment is fairly spacious for four people and has an enclosed balcony. The apartment's location is in the old town which is ideal for sightseeing and within easy walking distance of all the main sights. There are plenty of tapas bars and cafes for food nearby.
No WIFI, but this is noted on the details for the apartment. The apartment was very clean and tidy and had everything we needed. Would definitely recommend for a stay in Bilbao (a fantastic city!).