This is the place to stay in Bilbao: everything is absolutely perfect! The flat is amazing, a kind of "secret suite" right in the middle of Casco Viejo. You won't find a better place even in a 5* hotel and don't miss all Luisma's advices and savoir faire, he's a perfect host.
Probably this the best place I've ever been in all my trips whith AirBnb.