Frank's place is in a great location in Barcelona. Very close to the Rambla and many other sights in the city. The Chillax apartment is clean, and very spacious. I compare all of my AirBnBs to the alternative - staying in a stuffy hotel room. Frank's place is definitely a value compared to a hotel room. It has so much space to spread out and to relax.
While the apartment is in a great location, if you are a light sleeper, you may want to be aware - like most of the European apartments I have stayed in, the walls can be a little "thinner" than the walls you may be used to in the US. Sound transfers just a bit more than what I experience at home.
We were exhausted our first afternoon in Barcelona, and came back to take a nap late in the afternoon before heading out to dinner that evening. While my wife (who is normally the one to hear everything in her sleep) was able to rest, I had some issues because I could hear kids playing soccer (or some other sport) out in the courtyard behind the apartment. Again, this wasn't a big deal, and is entirely expected for kids to be out having fun during a beautiful early spring day (I don't want to sound like a curmudgeonly old dude). And, it's not really something that Frank could control anyway. Things were quiet at night, so this is just something to be aware of if you might be the type to sleep during "normal" hours.
In all, you can't go wrong staying here. Would definitely book a return stay here if I'm ever back to Barcelona.