I enjoyed my stay! It's in a good location for public transport (trams and underground trains) and one of the hop on hop off bus stops is a 2 minute walk away. Vienna is a big city, so its not walkable in my opinion, but this location made it easy to get everywhere.
As a solo female traveller, I felt safe and comfortable. There's a Thai restaurant on the ground floor, so there are often people around which is nice for the vibe.
I haven't given 5 stars because the fact it's all automated is a bit annoying. You have to check in online to get a code and there's no desk or office nearby to talk to a human. I had problems checking in and the AI support was really good though.
Lastly, there is underfloor heating in the bathroom! Winner haha