The apartment is convenient even if it is a bit old. I think if you're an experienced traveler you will love it.
the metro is a little bit far for people who don't like to walk but it was not a problem for us.
We also had access to the lovely garden, unfortunately the weather was not nice but at least we had one breakfast enjoying the morning sunshine.
The problem was that we were not told that the internet connectin was not working in the apartment. We figured out the last day. So the wifi is only in the garden.
I still recommend the apartment as it is not expensive for Vienna.