Paz' flap is a decorated and romantic flap, you can see many artwork from herself, it's suit for the couple who is in honeymoon or want to enjoy the time when stay in the flap, otherwise there is a comfortable terrace you can sleep there to pass a afternoon.
By the way the metro is just take 7mins to get, it's also very convenient go to to the center.
Anyway, it's worthy if you want to enjoy Barcelona slowly not just for sightseeing, then it's will be a very good choice!