We stayed in Don and Jaco's flat for two weeks. Overall the flat was fine, tidy and everything was easy to find. The kitchen was rather minimally equipped, but otherwise clean and spacious.
During our stay load shedding was mostly stage 6 (multiple times a day, up to 4 hours each) for which the flat certainly is not prepared - compared to my experiences elsewhere in Cape Town. There are battery lights, which either last for only an hour or are about as bright as a smartphone screen. WiFi has no battery.
The area - Observatory - is a rather safe as well as lively area of Cape Town with shops and restaurants. Still one should not walk around in the dark, alone in remote areas etc. as almost anywhere in Cape Town. We chose it for practical reasons (being near the place I worked).
Contact with Don was very nice and uncomplicated at all times + there was a late check-out option :)