Martha's apartment was fantastic for my stay. The area is really fantastic, easy public transport, great supermarkets, a good gym and many wonderful cafes and restaurants are all within a 5-10 minute walk. You're one stop away from Karlsplatz on the U-bahn, so it's incredibly easy to get into the centre of town too.
The apartment is clean, well furnished, and there are plenty of utensils and kitchen items to be able to cook at home. The hot water and internet were always fantastic. The area is peaceful and it's great if you want to be able to relax after a day of tourism or if you're in Vienna for work.
I would absolutely recommend the apartment, and would very happily stay here again next time I am in Vienna.