We found Martin to be a particularly good host. He picked us up from the airport on the night of our arrival; given that it was rather late on Boxing Day, this was greatly appreciated and reduced our worries about the transfer. He provided plenty of information on getting around in Berlin, alerting us to the possibility of group tickets for the U- and S-Bahn, and told us about the Christmas market on Gendarmenmarkt. Martin had had some problems with plumbing leaking down from the upper floors of the building just before our visit which required him to strip the apartment. He provided us with the rooms next door--a slightly larger space. It was spotlessly clean. As our return flight was rather late in the evening, well past the check out time, Martin arrange for us to leave our luggage near the flat; we were then able to race around on the last day unencumbered by suitcases. The only small complaint--which did not impinge on our enjoyment and which is nothing to do with Martin--is that there was a slight smell of smoke (from outside? the pub nearby?) in the kitchen and main room. The location was really good. There are supermarkets (open quite late) and restaurants nearby; Martin was able to point us in the direction of the better ones. The U-Bahn is just a couple of minutes away; it seems that everywhere in the city is a roughly 30 minute journey. We would wholeheartedly recommend staying here.