The apartment is in a ridiculously good location, literally three minutes walk from the centre, and it is generally comfortable, however at my time of staying the extractor fan in the bathroom didn't work, which made using the bathroom very uncomfortable. Additionally, the second bed, or sofa bed was quite uncomfortable to stay on too.
I had no problems with Luka in terms of contact or attempting to arrange things, the check in and out was prompt and swift.
The main issue with the apartment was a lack of wifi, despite being advertised as otherwise.
The wifi is not constant but part of a top up system, 1gb for however many so dinars. The wifi was never sufficiently topped up and for two days we had none at all, which was incredibly problematic for trying to arrange meeting friends, contacting family and generally trying to relax in our down time! As we were foreigners in Serbia we also didn't have any mobile data, so we were essentially offline for long periods, which proved extremely irritating and difficult for me and my friends.
I would definitely recommend the apartment and Luka, however I strongly advise he addresses the above issues.
Daniel &a friends