The place is centrally located. Walking distance from Fontana Metro station. The hosts are fantastic and would definitely recommend staying with them again. The accomodation is well-appointed and clean.
You do have to climb 6-7 steps to reach the elevator. Its not a major issue though. The apartment is on the 3rd floor.
Two small negatives are that
1) Bathrooms do not have latches/locks. This is a problem when there are pesky kids in the house.
2) Rooms are small -- but I guess since it is Barcelona, space comes at a premium.