In my opinion Xavier is always a super host. If u have any Problem he solves it in hours. The Flat was absolutely clean and its the best to stay in Barcelona. Poble Sec isn‘t full of tourists then for example Barceloneta.
The Flat is quite near to the center (Metro Line L3 only needs 3/4 stops to Placa Catalunya / La Rambla. Furthermore u only need 5 mins walk to Montjuic / Font Magica which are my favorite Places in Barcelona.
Hope to stay there again - soon.