Martin was the all time best host I have ever encountered. He was always very quick with replies before and during checking into his apartment. He gave us perfect directions from the airport and let us have an early check in. He had everything you would need in the apartment from shampoo to some milk and ice cold water.
He had maps of the city as well as the metro system. He highlighted the must-dos in Berlin, gave us some great places to eat traditional German food and cheap places to grab a drink.
He was extremely friendly and accommodating and it was a pleasure meeting him.
His apartment is walking distance to checkpoint charlie, potsdamer platz, Brandenburg Gate with everything else just a good 15-20 minutes away.