We were two couples that rented this place for a few days. Jeronimo was quick to reply to all the questions we had, and he was very helpful.
The area is great; clean, quiet, close to the Sagrada Familia and with really good connection to the metro network. Everything you need is around the corner (there are many corners in Barcelona), shops, supermarkets, nights hops, cafe's, everything.
The apartment is cozy and clean but it's a bit small for four people. If you need to sleep on the couch it might get a bit uncomfortable after a few nights.
The small balcony is perfect for the morning coffee, provided your dimensions permit it. The A/C is a blessing in the hot summer days.
All in all, I wholeheartedly recommend this place.