Overall, this is a very nice apartment, and the potential for a great (5-star) experience is certainly there. However, I have to give MY experience a 2-star rating, because of some major flaws - and the landlord's failure to fix them even when they were pointed out.
THE GOOD
* Location! This is right at the end of the Rambla close to the metro station, tons of shopping, food etc. Oh, and there is a bus directly from the airport to Plaça de Catalunya, which is right next to the apartment. It really doesn't get better than this.
* Spaciousness. The apartment was quite big and could easily accommodate our group of 5 adults and one baby.
THE BAD
* Fridge not working! This was a major deal-breaker for us. One of the reasons we chose to book an apartment and not a hotel room was to have a functional kitchen available. When you have a 1-year old, you want to be able to cook at home in the evening, because it is hard to go out for dinner when the baby is sleeping. Also, you want to have fresh milk etc. available. The woman who checked us in was aware of the problem with the fridge and said she would have someone fix it. This, however, didn't happen, and we had to write back to inquire about this. They finally responded that it would not be possible to fix the fridge until after our departure. I wrote back and explained to them that the lack of a fridge was not only inconvenient for us, but also made our stay more expensive, since we were forced to go out for all meals instead of eating at home. Instead of, say, reimbursing us, the landlord didn't even respond to this message.
* Toilet not working. The toilet in the bathroom next to one of the bedrooms didn't flush. Since there were other toilets available in the apartment, we could live with this, but it certainly was not as advertised.
* Other broken things. There were a bunch of other broken things that proved that this apartment has been rented out quite a lot. Some shower curtains were broken, which entailed a wet floor after showering. The TV didn't seem to work (at least the woman who greeted us when we arrived did not know how to make it work). There are several broken light bulbs.