Staying at Klaus and his flat mates apartment was such a pleasure. My friend and I got in from Prague at 4:30 am and Klaus stayed up to let us in and graciously have is coffee and couches to sleep on even though he was also hosting another guest in the room still. His flat mates are amazingly helpful not only for Vienna but for other cities in Europe that we were going to visit as they are all very well traveled. They even provided us with extensive advice and a map of our next destination of Budapest. Would definitely stay again if I am in Vienna. Thanks for being such great hosts!