Martin/CheckVienna was a good host; they responded quickly and correct. Check-in regulations were rather strict (had to send proof of Corona-vaccination/negative PCR) but not complicated.
The apartment was clean and well equipped - towels and shampoo+soap were provided. There’s a supermarket across the street and the subway is only a few blocks away.
The price - especially compared to a hotelroom - is worth it. We recommend it for sure!