Can't recommend 105 Doric enough. The location is great with a couple of supermarkets and numerous bars and restaurants nearby (make sure you check out Giovannis Deli for breakfast/lunch (the coffee is great) or some great food to bring back to the apartment for dinner). It is a short walk to the Waterfront and we felt very safe walking back in the evening while it was still quite light.
Nick and Tanya were super friendly and helpful. Make sure you check out the guide they've put together which is very useful and has some of the top places to visit in Cape Town. It's nice and concise which helps as you can really get bombarded with too much information when trying to decide what to do in Cape Town.