Klaus was a great host. He is incredibly kind and attentive. The bedroom is very neat and clean, with everything you need to have a comfortable stay.
He is also incredibly knowledgeable about Berlin, which leads to some great conversation and top notch advice on everything from where to eat to what to see depending on your specific interests.
The location as well is in a great part of East Berlin, only a couple minutes by tram from the Berlin Wall. The neighbourhood as well has its own eastern feel to it, so you can really feel the difference, especially if you're travelling from Western Europe.
All in all, I'm very more than satisfied by my stay with Klaus, and I hope to stay with him again next time I travel to Berlin!