We have stayed at the Charming Room for three nights. We have not met Roman but we communicated easily through message. His assistant, a nice lady, introduced the apartment and the facilities to us clearly.
The location is good and it is only 6-7 minutes walk from the Rochusg. metro station. Alternatively you can reach the Wien Mitte Station by foot less than 15 mins. A supermarket is just opposite to the building and you can buy food for cooking in the apartment yourself.