I had a great experience in this apartment and with Stay U-Nique.
Check-in and check-out were completely smooth. The apartment was exactly as advertised, in a great location very convenient to La Rambla and the L3 metro. Everything was extremely clean and in working order. Stay U-Nique is extremely responsive and easy to communicate with: the one thing that wasn't perfect was that the air conditioner broke mid-stay, and when I told them, someone came to fix it within 24 hours -- you really can't ask for anything more than that.
When I come to Barcelona again, I will definitely stay with Stay U-Nique. They are some of the most professional hosts I have ever had on AirBnB.