I stayed in Monica's apartment for just under a week, as I was attending a dance festival in the Poblenou area. I found Monica to be a warm and attentive host, and the apartment itself could not have been more perfect. Monica was actually away during some of my stay, but before she left she ensured I was made to feel very at home, and that I knew where everything was; how everything worked; and how to contact her if I needed to.
The flat itself is perfectly located. It is very well connected (1 minute walk to the metro, which takes you straight into the centre), a 10-15minute walk to the beach, and a 5 minute walk to the big Mercadona supermarket (great for me as I am coeliac and they are excellent for gluten free!) There are also other supermarkets nearby.
In addition you are 3 minutes walk from the main street in Poblenou.
The apartment is up several flights of stairs (no lift) - worth being aware of, if like me you don't tend to pack light(!) - however, when you get to the top it is definitely worth it! It is a light and spacious apartment, with a lovely little terrace. The bed and bedroom are small but comfortable, and there are three large drawers, as well as a few clothes hangers/hooks for hanging your clothes.
All in all I cannot recommend Monica's place highly enough, and I definitely plan to return next time I am in Barcelona.