Michael's place is excellent and I would definitely recommend it. The apartment is miraculously clean and the bed very comfortable. It is bigger than what it looks like in the pictures. Despite the fact that we visited during late December it is very warm inside the apartment as it is well insulated.
The location is convenient, quite close to the center, with a museum dedicated to Schubert just around the corner (2 min walk on Google map), an art house cinema nearby, super markets, restaurants, and other shops in its vicinity. The area is safe, quite, and convenient.
As to the host himself Michael is very communicative and flexible with our check in time. We didn't have any issue during our stay.
I had a really enjoyable stay with my friend and would definitely choose this place again when I am back to Vienna the next time.