We definitely recommend Alfredo's place. The flat was artistically decorated and well supplied and very clean. Really enjoyed having the windows open and hearing the city of Barcelona below (but it is a relatively quiet side street!). There was air conditioning when we needed it.
The location was perfect for us and we enjoyed walking around the city. There are several nice restaurants for casual food. Onia Cafe was great for lunch and their peanut butter cookies are great. I would just note that once out of the elevator you will still have a few stairs before the doors to the unit. Overall a great place to stay and we would return again.