The hotel is in a perfect location: center of the city but still very quiet. Everything worth visiting is within walking distance, including public transportation and the stop for the bus to the Frankfurt Airport.
The breakfast is very nice and worth booking. Coffee is available for free throughout the day.
The hotel is very clean. The bathroom for the single room is a bit small but also very clean. Nice shower.
I have stayed here several times and will always come back when I am in Darmstadt.