We had a really great time at Sophie's place. We didn't get to meet her, but Fabian was awesome; we arrived very late at night due to a flight delay, and he was very patient and received us with a smile. He was also very friendly and helpful, and went above and beyond to ensure we had everything we needed. He's a great host.
The apartment is great. Public transport within a couple of blocks, and walking distance to the old city center. The bedroom's window opens to an interior garden. It's a nice view, and very quiet. The bed was comfortable, and there was a fan available.
Everything was very clean and tidy. The kitchen had everything we needed, the water heater worked like a dream and we didn't have any problems with the WiFi.
We're very happy with our stay, and we can't recommend it enough. Great place with an awesome host. If we're ever back to Vienna, we'll absolutely stay here again.