The apartment is in a wonderful location in Bilbao. Literally a few minutes walking to the Guggenheim, and to tens of great places to eat and hang out in central Bilbao. It makes for a great base.
It feels also very new. New furniture and appliances, and like new flooring and painting. It's impeccable in that way, and it was also very clean and tidy when we arrive. The hosts made an effort to make the decoration interesting with a theme of VW buses, surfing and music. While I can find that cheesy sometimes, I did enjoy reading through the books on VW bus history and the Spanish comics.
The bummer for us was the lack of natural light. The apartment is located in the first floor of a traditional 6-7 stories apartment building, with windows only to inner patios. The entrance to the apartment was akward, being located in the lobby of the building itself. Maybe if it was described more transparently in the apartment description we wouldn't have been disappointed, but the lack of natural light gave a certain sense of claustrophobia, and we didn't feel comfortable resting in the apartment during the day. On the other hand, the location makes it a perfect base if you don't plan to spend much time in the apartment.
The welcoming was really warm and spot on: they were available as we landed, and super responsive over the phone.