I met Anastasia's sister to checkin, which went smoothly. She was easy to get in touch with and we met outside the apartment at the agreed time. It's a bit annoying to have to pay €30 extra in cash just to checkin after 9pm, but the extra charge is stated in the listing.
The flat is well designed, feels more spacious than it appears in the pictures, with high ceilings and big windows.
It can be noisy, especially on Friday and Saturday nights so probably not the place to stay if you're looking for an early night, but location wise for access to bars and nightlife of Chueca and surrounding areas it's perfectly placed. Chueca metro station is a stone's throw away. There's a little supermarket and shops nearby to buy any essentials needed.
The wifi was fast and reliable.