The Apartment: We stayed in the red and brown unit. Based on the pictures, I thought I would like this unit the least, but it turned out to be quite lovely, well-appointed and comfortable (except the couch), with three tiny balconies overlooking Carrer Petrixol. Most significantly, based on the pictures, I believe it has the largest bedrooms, especially the second bedroom (not large, but not quite so claustrophobic as in the other units) with a pull-out trundle instead of bunk beds. Overall, we found the apartment to be quite nice and very spacious for a mother-daughter two-person 7-night stay. I think it also would be fine for a couple and a third adult or a couple and two small children, but after that, too crowded for my tastes. Lots of storage space in the bedrooms and bathroom. We asked for and received extra pillows and towels. The kitchen met our needs, but I agree with other guests that having a few more basics (sugar, salt, cooking oil, spices, paper towels) on hand would be nice, as well as a few more kitchen tools (no vegetable peeler surprised me). Plenty of windows, though not very bright due to how narrow the street is and the unit being only on the 3rd floor (American style/1st floor Spain) - but lots of lights in the apt, which is great. FYI, laundry is combo washer/dryer so takes a bit longer.
Location: walking distance from three different metro stops, many of the sites in the Gothic Quarter, and just 3 minutes to La Rambla. Carrer Petrixol is famous for sweets and desserts of all kinds - enjoy! As others have stated, it was noisy some nights, quiet other nights. Earplugs and the white noise app on my phone did the trick if we wanted to go to bed before it quieted down. Also convenient to a large grocer on La Rambla (Carrefour?)
Customer Service: as others have stated, this was uneven. They were very nice at check-in, including storing our luggage while we waited for the unit to be ready. However, we never received a message or call as requested to let us know when it was ready. Also, we sent several messages through AirBnB and email that did not get prompt responses or responses at all (this is in sharp contrast to most other AirBnB hosts who respond right away!). My advice is to call instead (understanding that international calls on your cell phone may not be cheap!) And when we had an after-hours problem with the laundry machine, no one picked up the after hours phone number at all! Also, there were no instructions in the unit as to use of the laundry or dishwasher or anything else - no guidebook to the area or the building or anything. (But of course, you can look up anything you need on your smart phone these days.)
That said, for the money we paid, I thought it was overall great value for such a prime location (though maybe prices were lower due to COVID) and I appreciated the very flex cancellation policy in view of COVID.