We stayed at Osnat appartment in June first week. The home is close to Praterstern underground and accessible by bus 5B from there. Stephanplatz (city centre) was 3 station away. AC in both living and bedroom helped a lot as the weather was warm during our stay. The appartment was aesthetically done and kitchen had all equipments.
Nothing much negative about the place except occasional tap leakage and dining chairs were a bit wobbly.
Though it was clear that early check in is not possible.... If possible please do provide a early check in as 3 pm seems a little late to start the day