We loved staying in Sela's apartment!
First, the location was really great -- very close to the metro which made it really easy to get around Barcelona, including the Barca Chelsea match we attended at Camp Nou! It was also an easy walk to most places when we felt like exploring on foot. It's particularly close to Park Guell and other spots near the Gracia neighborhood. The apartment itself is in a much more quiet/less touristy neighborhood with convenient and reasonably priced grocery stores and cute restaurants all within a couple minutes walk. Our favorite restaurant was a cash-only spot called Gasterea that we went to three times during our one-week stay, we loved it so much.
Second, Sela was incredibly responsive! She was very accommodating with our travel schedules: on arrival, our plane landed a little earlier than the check-in time; on departure, our flight was canceled and the airline put us on another much later flight -- Sela helped us store our bags so we could explore the city for a few last hours rather than sit in the airport all day.
As others noted, the apartment itself is cozy, but perfect for two people who are visiting Barcelona and plan to explore the city all day. A huge plus is that there's an elevator in the building, so no need to haul luggage up and down flights of stairs. The apartment was very clean, bed was comfortable, the water pressure in the shower was great, wifi and cable worked perfectly, and there was a washer & dryer in the unit. We didn't try to cook anything in the kitchen (so many great restaurant options), but we did keep leftovers in the small refrigerator.
Everything we needed for our five days! Would definitely stay with Sela again.