CLOUD NR. 9 and Emil are both great and made my visit to Vienna very pleasurable. It is a very clean, modern, and quite place to stay, especially considering that it is so close to the city center and a key underground train station (both only a 2-3 minute walk from apt). Also, there are some decent markets and restaurants very close by. I particularly enjoyed having morning and evening espresso while looking out over the roof tops of the neighborhood. Also the balcony made for a great location to watch a massive thunderstorm pass through Vienna! It is over 8 floors up from the street, and has a lift to get you there. Though this is my first trip to Vienna, I do know many friends who have stayed in other apts and hotels, and I think CLOUD NR. 9 is still a best option. Highly recommended accommodation for Vienna, especially if you want to be close to the old city center.