Great appartment (brand new) and conveniently located at 3 mn from Plaza del Centre station or 5 mn to Sants station. The subway will lead you to the city center (la Rambla and Bario Gotico) in 15 mn maximum. We've stayed there with our kids for 3 days and everyone enjoyed the city and an appartment is much more pleasant than staying in an hotel.
I definitely recommand this place and the host who is very welcoming and professional.