My friend and I visited Vienna for two nights and stayed in Gerd's apartment. Gerd himself was not in town during our stay but he arranged for his friend to check us in and communicated excellently throughout the whole process. The apartment was well located; very close to Belvedere Palace and within walking distance of the main sites. The neighborhood itself was safe which was important for two young women traveling alone. Additionally, it was very clean and definitely large enough for two people.