Very recommendable!
Andrija is communicative, in a very clear, helpful way.
The flat is less than five minutes away from Ubahn station, which is a relief, and if you like walking, in less than 15 minutes you'll get to the riverside. In walkable distance, there are also a couple of local cafes with good-tasting coffee and away from the tourist crowd which I found at Andrija's recommendation and enjoyed very much.
The flat and the room were very clean and organized, just as it shows in the photos.
My only complaint would be the lower-than-comfortable room temperature, which is understandable in such old building, so it would be great to provide guests with an extra blanket, just in case.