Sofia's place is a nice place to stay for the family and close to the most sites and Train and Bus stops. Sofia is a very nice host and answers any question you have immediately and also very helpful. She also let us into the building earlier than expected. One word of caution about Barcelona though that you have to be very mindful of your belonging in the train stations as there are quite a few pick pocketing going on there. Barcelona itself a beautiful city and the historic sites are amazing.
I would book my stay with Sofia again if I go to Barcelona.