Andrei was very accommodating to let us check in early, so that was a great relief for us arriving by an overnight train. The apartment is very spacious and nicely decorated, and has a homely feeling to it. The location can't be beat: everything that a first time visitor to Vienna want to visit is within walking distance. The free city bike station is just a block away and we took advantage of that for longer trips.
A slight drawback is the hot water for the shower: the water pressure doesn't appear to be enough to kick start the boiler if you aren't going for full hot water. It took a bit of tinkering and with the help of turning on the faucet that we could find an optimal temperature. There is also no fan in the apartment, combined with it being on the first floor (therefore noisy street traffic), it was a bit stuffy on the days we were there.
Overall it was a pleasant stay and the location is prefect!