I spent 8 days in Bilbao, visiting the city, working remotely, and attending a professional conference.
I've walked everywhere (you need to be prepared to walk in Bilbao), I have gone to Portugalete by public transportation, I have gone to Gaztelugatxe (outside Bilbao) by Uber and bus.
I may say that this apartment has an excellent location, regardless of your travelling interests. You may walk to Guggenheim Museum in less than 10/15 minutes, to Casco Viejo in less than 30 minutes and you have many options within 5 minutes walking to public transportation (bus, subway) to go anywhere. The location is also easily accessible for taxi/Uber, if needed.
The room is spacious and bright, with a generous window and a comfortable bed, I could even use the vanity table as a working desk.
The bathroom is spotless clean (as the entire appartment).
The fruit, cookie and tea breakfast left in the kitchen by the hosts each morning was all I needed to start the day and made me feel well taken care of.
Jorge gave me some great hints on sightseeing, and Maria was very supportive throughout my stay, especially with my early check-in and late check out, to accomodate the schedule of my flights.
I truly appreciated their generosity, availability, responsiveness and discretion.
If you dance argentinian tango, don't miss the tango studio/cafe accross the street. The hosts there are as charming as Maria and Jorge.
The only downside was that we didn't get a chance to talk and get to know each other a bit more, due to our schedule (some days we didn't even meet). I hope there will be a next time. :)