This was an excellent place to stay. It was spacious for our needs and very comfortable. The kitchen was quite ample for our stay, although it did not have all utensils that one might need (e.g., I didn't see a peeler). Note that there is no microwave or freezer in the kitchen, which wasn't a problem for us but could matter for some people.
The access to transit was very good; many attractions were about 30 minutes away by transit. There were a number of restaurants, grocery stories, and bakeries in the neighborhood.
The temperature in the apartment was fine day and night, when highs in Berlin were in the mid-70s Fahrenheit and in the 60s at night. I don't know how it would've been during a heat wave.
We didn't really use the basement but I should note that the stairs down are extremely steep-- almost a ladder instead of stairs.