I spent three amazing days in Alf's room. The room is as described, very clean and quiet. It's ideally located to explore everything in Bilbao by foot in no time (besides, there's also a bus station at the doorstep).
I was very warmly welcomed and received a super introduction to the city, its background and culture including some funny trivia and most of all where to get the most delicious pintxos.
Super experience, I fully recommend it.