It is really great place to stay in Barcelona. It is really close to the metro (5 mins walk) and buses (literally just before the building). If you prefer walking, you can reach nearly every main BCN attraction within 30-45 mins.
Things like shops, pastisserias and restaurants with breakfasts are nearby. There is even market with fresh vegetables, sea food etc just 5 mins away.

Apartment is completely equipped - there is fully functional kitchen with all accessories, including toaster and microwave. There is washing machine with drier. Very comfy thing. My wife now wants something like this at home :)
Bathroom is a bit narrow, but it's matter of getting used to it. There is no bathtub - only shower.
There is a safe in the wardrobe. We didn't use it though.
Apartment is located on the 4th floor. There is a lift, but it is small. Might be important if you plan to go with baby stroller or need to use wheelchair.
Don't expect spectacular views from the windows though - window are towards interior of the building. Which has also good side - apartment is really quiet. We slept with all windows open and hear no cars. And hey - who is coming to BCN to sit and stare through the window anyway :)
Summarizing - really cool place for people who are coming to visit Barcelona