SUMMARY - excellent location, lovely apartment, would stay again.
LOCATION/CHECK IN - Great location in Eixample 2 blocks from Passage de Gracia and Casa Mila. So lots of shopping 2 blocks East, lots of little bars and restaurants 1 block West. Literally right on the Provenca underground but we never used that, walked everywhere. Check in was good for us, the guy turned up in like 5 minutes after we got there, but there's no actual check in desk or anything so you need to read the instructions (couple of times we saw people who were checking in looking a bit lost).
APARTMENT - awesome, 3 good sized bedrooms, 2 bathrooms, plus kitchen and living room. My wife used one of the bedrooms for a dressing room, and we had a bathroom each. The kitchen was very nice, we used the coffee maker and bought in daytime food/snacks from Bon Preu (grocery) 3 mins walk away. We carefully moved the kitchen table to the living room because we were working from there. Excellent solid WiFi although it bugged out twice during our stay but was fixed quickly in the morning. NOTE - the apartment was very clean and recently modernized with nice appliances etc, nice showers and so on - but if you are looking for an American hotel style luxury thing, this isn't it - it's a tastefully done upgrade to an old building, clean, modern, but sensitively keeping features such as the beautiful tile/wood ceiling, original floor tiles, etc. So if you are looking for clean/modern but still want to enjoy that Barcelona "feel" this is for you.
AREA - right in Eixample. If you're familiar with the area, Gracia is a 5-10 minute walk away which is a great little hipster area. Eixample has so many really good restaurants, but it's still pretty hard to spend much money because everything is pretty cheap (Wine is like 12EUR/bottle). Walk to Barrio Gotic or down to the beach in 45 pleasant minutes.
COVID/MASKS - Vaccination rates are very high in Spain/Barcelona (as of Sep-21 approx 75%), and people naturally wear masks in stores etc without complaint and case/death rates are low and going down. So if you are anti mask/anti vaxx then please just stay at home, people in Barcelona are getting on with their lives thanks very much. Bars/Restaurants are all closing at 12:30am as of Sep-21 which is very early for Barcelona which is normally a late night city. So again, if you're looking for all night stuff, best leave it until 2022 when things will fully re-open.
NOTES - 30 mins from the airport. Get a taxi, they're cheap and plentiful. Uber/Lyft doesn't operate there because the taxi unions are pretty strong, but actually it's not a problem - you can always walk everywhere, or flag down a taxi, or if you want an Uber style app you can use FreeNow which calls taxis - although really not needed. Also download Google translate, this is a living city, so some people speak English but many do not - so good opportunity to learn the language.
CONCLUSION - awesome, one of the best cities in the World, and a great place to stay.