We had a very enjoyable stay at the Penthouse apt. First the positives. Location was absolutely perfect. It's a block away from Casa Batllo and pretty central to everything else. It's a quick 10 minute cab ride from most places in the city. There are tons of restaurants and bars right near by. There are also many supermarkets on the block, which is great to buy water, wine, snacks etc. The apartment itself is very clean and comfortable. We had two adults and two kids and it was very spacious. The balcony is awesome with great views of the city. There aren't many apartments like this with a penthouse balcony.
A few challenges to this apartment. The elevator does not go all the way to the actual apartment level. The apt is above the Attic level, so the elevator goes to A and then you have a set of stairs to the apt. The slider doors to the balcony don't have a handle on the outside, so it's tricky to open back up. These are just minor nits on an otherwise great place.