We had a pleasant stay at Alba's house. It has a fantastic view of Sagrada Family right from the balcony. My 9 year old son also loved it!
Location is convenient as it is right out of the subway exit. There's a supermarket within 5 mins walking distance and a very close bakery.
House is even bigger than what it seems in the photos and comfortable.
Only concern we had was, there's no central heating, only A/C and an electric heater, it was not cold, but it was damp, as the flat does not have direct sunlight.
Could be great for warmer and hot months though.
Stairs did not bother us, it was also mentioned in the flat info section, and that's the case in many of the older buildings.