You cannot beat the location of Armando's place. Every morning at 9am you are awoken by the sounds of the bells from Sagrada Familia. The view from the balcony is fabulous. It is an older building but has an elevator and modern appliances. My two boys appreciated that they could each have their own room.
It is close to the L5 and L2 stops (I think), so it is very easy to get around Barcelona. I highly recommend doing a bike tour-the city has the best bike infrastructure. The apartment does not have air-conditioning, but normally cools in the evening. There are ceiling fans in all rooms. We only had problems on one night, when all of Europe was hit by a terrible heat wave.