Karl was a fantastic host, with excellent communication where needed. Prior to my stay, Karl sent me some information on Berlin which helped in deciding what to do. There was also some tourist information in the apartment.
The apartment itself was clean, well stocked and well set out. The basics such as tea, coffee, cereal, spreads and showers basics were there if needed which was very helpful!! Whilst I was not in the very heart of the centre, the apartment is very well located, literally a 2 minute walk to the train station. Trsins were running every 5-10 minutes most of the time and also all night. From that train station you are just 5-20 minutes away from major attractions such as Alexanderplatz, Anne Frank museum, the wall, Checkpoint Charlie and so on. It's location is a fairly quiet neighborhood.
I would definitely recommend and stay again! Grest value for money too!!!