Kolping house is well placed near to the centre of Kampala. I've stayed at this place on a number of occasions. It is frequently used by visiting U.S. church groups and medical missions.
It is very clean, secure, with very helpful staff, and a good value for the money. It is a bit out of town on Bomba road near bwaise stage.
I have always found it to be quite tranquil and peaceful, esp. in comparison to most of the other Kampala hotels I have stayed at.
However, there is a nightclub next door, so based on the other reviews I wonder if they have a new sound system.
Earplugs are essential for any traveler to Kampala, in any case.