Alex's place is great! It's immaculately clean, in a great location, and, as others have mentioned, Alex is a great host. He is very responsive, friendly, and genuinely tries to make your time in Barcelona as good as possible. He also offered to let us store our luggage past checkout and come back later to collect it, which we really appreciated!
A few things to note: the hot water ran out in around 10 minutes. It was explained to us when we checked in that it would last for around 20 minutes at a time and then take another 2 hours to fill up. Not sure how this would work out for more than 2 people staying there (which was our case). The price wasn't cheap, so we would've liked to have at least been able to take normal showers.
Even though he's installed double-paned windows as has shutters on the bedroom window facing the street, there's a fair bit of noise that still enters that room and the apartment. Depending on how sensitive you are to noise, you may or may not notice this. The other bedroom closer to the front door has a window next to the main staircase and open area that goes from the entrance all the way to the top of the building, and there's a fair bit of noise that comes in that way from people entering the building, talking, etc.
All in all, it's a great place and we appreciate him having us!