Stayed for 9 days with my wife.
+++ good location regarding the airport, metro, buses, boats, city center, etc. The bus from airport arrives at bus terminal (4 min walking distance from the hotel). The bus ride airport ->hotel lasts 15-25 min and comes every 15 min and costs 3 EUR. From the same station you can take buses to a wide variety of destinations in Spain, France, Portugal;
+++ walk to city center (old city) lasts 20 min - really close;
+++ plenty of places to eat day and night near by the hotel;
+++ 3 min walk to the Athletic Bilbao stadium (for football fans);
+++ possible late check-out and luggage room (free of charge);
--- old looking, untidy, smelly place;
--- the view from the room is towards other apartments;
--- constant smell of food and garbage in the room;
--- no vault in the room so you have to keep your valuables at the reception, "guaranteed" by receptionist's "signature" :))