Oscar and Marta's place is really comfortable. The location is fantastic - easy walking distance to the Guggenheim and the Old Town, just a few steps to the Makito metro station (where you can get a train to San Sebastián or the metro just 2 stops to the Old Town) and very close to the Fenacular. Bilbao is a beautiful city - small enough to walk around, but lots of interesting things to see. The Guggenheim is spectacular - don't miss a visit.