The apartment is fantastic, it has everything you need the location is amazing. You are seconds away from the beach and the sea path. There are nice bars just on the other side of the street with good pintxos and drinks and the metro is close by. If you are taller than 6' (182cm) the bed may be too short for you. The location is what we loved as you can walk the sea path down to Puente Bizkaia or the other direction all the way to Plentzia, we did the path multiple times as it was beautiful. It was great being able to clean our clothes, just had to get used to hanging them on the clothes rack out the window, became a pro in no time.
If you want a quiet place to stay outside of Bilbao this is a great option. It's about a 20 minute metro to Bilbao.