Peaceful place, we felt right home. Heating system is very effective, makes the place warm in minutes. Water pressure in shower is satisfactory. Kitchen appliances are not much but enough to prepare a nice breakfast or appetisers to go with drinks. King bed and sofa are comfortable. Pillows are ok but some people -like me- may require two of them since they are pretty thin.
Location is great, walkable distance almost everywhere in Mitte (within 1,5km) Thorstrasse is stone throw away and you can find many restaurants nearby. I would strongly recommend this apt even for long stays in Berlin.