We stayed at Sebastian for a week and the apartment is really nice, having everything that you need. It is located in a neighborhood with many foreigners so you see a lot of diversity. We found it very helpful that Billa and Spar were near the building. The metro is 5-10 minutes and the tram is 2 minutes and it takes you directly to the city center. If you like walking, the Rathaus is at a 35 - 40 minutes walk. If you are a bit loud, you like staying in the house and party indoor, this might not be the best location for you because it seems like you can very easy disturb the neighbours. I didn't got the chance to meet Sebastian but he was very nice and provided us with everything that we needed to have a lovely stay.