The apartment was easy to locate, about 5 min walk from Volkstheater underground stop. On arrival Gerhard met us and showed us around the clean, bright loft apartment. Gerhard was very accommodating and quick to reply prior to the trip; he even loaned us an iron.
Public transport is very good in Vienna and the apartment is well located to avail of this.
One small drawback if you have trouble sleeping is that there is no blind on the skylight over the bed so packing an eye mask would be recommended.
Overall, we would definitely recommend staying.