We spent four nights in Christoph's flat in Vienna, Austria. The location was excellent, 2 minute walk from Karlsplatz underground station, which meant it was very straightforward in getting there from the airport. The flat is within walking distance to the Museum district, Belvedere, and the Hofburg - we barely used public transport. The flat is very basic, no Wifi or TV, but it was warm, comfortable and clean which is all we needed - excellent value for money. Christoph also allowed us to leave our bags in the flat before the check in time so we could go out and explore which was great.
The only downside was that there wasn't a kettle so we had to heat up water in a pan on the gas cooker which didn't work properly and the blind for the window in the shower room was stuck which made taking a shower awkward.