Mario is a great host! He is very responsive and very helpful (we had to book a taxi because we were leaving early in the morning and he offered to do it for us -as our Spanish was rubbish) ;)
He also gave tons of tips for restaurant and city overall.
The place is really nice and central to Bilbao (and so close to Guggenheim!)
The flat was really clean and quiet so... I would definitively recommend it!
Thank you again Mario!