This is a good hotel overall, but not really a 4 stars, my impression is that they could do better in all aspects to get there.
The cleaning was not my problem, my room was clean enough, but the lobby couches were really dirty though.
Breakfast was really good, the location is quiet and calm, and the room is comfortable.
The biggest problem was not having WiFi internet in the rooms, which is pretty shameful for a "business" hotel.
The exhaust fan is very lousy, and remains on for a long time after you leave the bathroom.
If you need to have dinner, the restaurant is on the other side of the street and close at 22:00, but there were a lot of smokers inside there. which was disgusting to me.

In the end, if you go there expecting a 4 stars hotel, you may be disappointed.

Not really 4 stars level. We stayed 2 days there in business trip, then my corner room was noisy with the street activity.
No wifi in the rooms , which is not easy for business travel
staff is OK
I would suggest another choice next time as there is Mercure and Ibis in Graz

We stayed at the Hotel Bokan for a week in May. We may have been lucky but our room was modern, large and airy and everything was working. The hotel website does not accurately describe the facilities and the lack of coffee/tea making facilities and toiletries did not help first impressions. All the staff were very helpful and pleasant (especially the one person on reception who also made coffee and served at the bar!).
The location is rather isolated and although there is a frequent bus service the nearest stop is well away from the hotel. Overall our experience was good and we would stay there again.