The apartment was great. It was extremely clean, the space was pleasant, and the beds were very comfortable. The neighborhood is quieter than the central tourist areas, but there were still lots of shops and restaurants nearby, and it was very easy to take the metro to visit the major museums and other sites.
Communication was quite easy, even though it was each time we reached out a different person from SweetInn responded.
The only complaint we had is that we only had one set of keys for two travelers. Although we were supposed to be able to unlock both the building and apartment door with an app, the batteries in part of the system connected to the front door were dead, so we had to either coordinate with each other or text SweetInn and ask them to open the front door if the two of us weren't together.
Barring the issue with the keys, I would absolutely stay here again.