Petra's studio is a gem. We arrived around midnight and were welcomed as if it was 6PM. The studio is super clean and spacious: matching curtains and pillows, bed and sofa, furnished also with a big wardrobe in case you want to unpack and feel like at yours. The bathroom is a bit small but perfectly functional. The U-Bahn is 5 min walking from the house, while buses are literally around the corner. All the major attractions and point of interest can be reached in 15-20 minutes door-to-door. The studio is located in a residential area, thus it is very quiet although facing the street. I highly recommend it to those who want to spend more than a couple of days in Vienna.