The apartment in Vienna provided us (group of 8) with a great base to visit Vienna. Located near to the town centre (the Underground was close, but you could easily walk into town too), close to the airport train station and next to a large park on the other side of the adjacent canal.
The apartment is beautifully large, but has some minor issues to be expected with a building of that age; creaky floors, a slightly odd layout, aged bathroom/toilet facilities. The soundproof windows were fantastic, and the lovely morning sun was a beautiful way to start the day.
When arranging to meet for the keys, be very precise, we had some hassles there.
Amazing Lebanese restaurant not 200mm away - we ate there twice.