The apartment was perfect fo our needs.
Me and my colleague fell comfortable and found the apartment really well situated.
Mr. Petzke handled us the keys at the time we arrived at the apartment ( after having to change the arrival time a few times because meetings and flights), making it really easy.
The apartment has all the necessary to make your stay in Berlin pretty comfortable.
It is around 10-15 min walking to Postdamer Platz, and (i would say) 20-25 to Alexander Platz.
We enjoyed our stay at the apartment and would definitely consider it as a first option if we need to stay in that area of Berlin!