We (3) went to Bilbao for 7 days with uni and we had a total blast!
Location of the Apartment:
The Apartment is situated in the middle of the old city. A big super market, the 'Ribera' market and metro as well as tram stations are within less than 10 minutes by foot. The city center is about 10mins and the Guggenheim Museum about 30mins by foot, while the ways are incredibly nice to walk because of the nice athmosphere near the river. In the street itself are a lot of bars wich is very nice on the one hand but can also be very annoyingly loud in the evenings.
The apartment itself:
It had everything you need while being on the smaller side. The kitchen could have more utensils but you can easily cook your own meals. There are two bedrooms and a living room with a sleeping couch. One bedroom has a single bed (but can be expanded) and the other bedroom has a double bed. All of them are very comfortable and clean. The apartment is on the 1st foor and has a balcony from where you have a nice view into the old town street.
One thing we didn't like were the windows, because you could not lock them and they could be easily opened from the outside, however bilbao is a very safe, clean and nice city where incidents happen rarely.
The host:
Sadly Alex doesn't speak english, but the communication worked out alright in the end. He sent a friend to check us in, who spoke english very well and was able to tell us about the city and apartment. Alex himself was very polite and answered very quickly everytime we wrote him. We had no trouble when checking out at 04:00 in the morning because we could leave the keys on the kitchen table. Overall the communication wasn't easy but still worked well.
Overall i can really reccomend this apartment when visiting bilbao.