We have stayed for a week in Lucy's apartment. We were here not for the holidays but we were working at the same time while exploring Barcelona. Lucy's apartment had a great internet connection and it was very warm in the beginning of February. The outside area to have lunch was super nice during warm sunny days. The kitchen was equipped with all the stuff we need to make breakfast and lunch when we wanted to save time by not going out for a quick meal.
The place is located in the great location so everything is well reachable and is not overwhelmed by the touristic stuff that you can find next to La Rambla. The street is not noisy at all and it's quite calm neighborhood but you might here a motorcycle or recycling workers at night but it shouldn't disrupt anyone's sleep.
Communication with Lucy was excellent. She gave us tips on things to visit outside Barcelona. There were plenty of tips about places around. We have been greeted with warmth and there were no problems at all with the stay. Totally recommend!