If you see that this flat is available, grab it! My husband and I spent 5 nights there and loved it! Spacious, modern, impeccably clean apartment, windows overlooking the courtyard, nothing to distrurb your sleep. Funky bars and cafe in Gracia are a short walk away. Yes, you're not going to be living on a grand boulevard or a cobbled little street, but the neighborhood is safe and quiet. A really nice tapas bar on Carrer St Antoni & enGrassot. Lots of cornershops nearby, no tourists, reasonable prices. We would buy oranges and made ourself fresh juice in the morning - the kitchen's got all it takes. The ONLY downside: there was no kettle. For somebody who comes from a tea-drinking country (Russia), that's important.
The bedroom is separated from the living room by a sliding door. The A/C is in the living room, which we actually liked because I hate having to sleeping under an aircon. Worked fine for us.
I cannot recommend this place enough and I will definitely be writing to Marcos when I go to Barcelona next time.