Extremely disappointed by the staff: my personal feeling is that they are interested in your money, only. Too bad, because hospitality and kindness should be a priority for a hotel. I will not stay in this hotel again in the future.
For the rest, I have been in Am Parkring twice. First time, I was staying in a double room; second time, I was staying in a single room.
Double rooms are large and pleasant, with large windows, and they have a stunning view on Vienna.
Single rooms, instead, are small. You still have the view on Vienna, but you can see that view only if you are standing by the window (due to the size and position of the window). Therefore, you don’t enjoy that your room has a special view... because you see no view at all when you are, e.g., sitting at your desk or resting on your bed. Furthermore, furniture and bathroom are old and not interesting.
Hence, in my opinion double rooms are worth their price due to their size and view, whereas single rooms definitely are not recommended (for the same price you can get a much better room elsewhere).
All rooms that I have seen have a dark carpet on the floor, which I don't like at all for hygienic reasons. I don’t know whether the hotel has some without carpet, as well.
During my second stay, towels supplied were few and of poor quality (too old and not soft because washed too many times).
I haven’t had breakfast in the hotel, I believe it’s very good but it’s also rather expensive (19 EUR).