Germán was simply the best host.
He picked me up by car so I would easily make it to the accommodation. Upon arrival he gave me plenty of information on what to do, where I could go and how to get there by public transport. The studio was spotless and I felt both very safe and comfortable during my stay.
The location of the accommodation was great because of its proximity to the airport and was accessible by bus and metro. The only thing to keep in mind is that, though it's in a nice residential neighborhood, it's located on the mountain side, so you will have to climb up many stairs to walk back from the city center. However, this was not a problem for me, as I managed to walk everywhere, but I wanted to point it out.
I will be happy to stay at Germán's if I visit Bilbao again =D