We stayed in Robert's place for 6 nights and found it to be a nice, big flat in the basement of his house. It's got an open plan kitchen and living room with everything you need including a dishwasher, cooker, oven, coffee machine, tv, ironing board etc. The one thing that could be improved is the wifi as it was often very weak or wouldn't connect at all.
Robert is very friendly and came to greet us on our first evening and gave us some helpful tips for what to do and see whilst in Konstanz. The flat is a couple of minutes walk from the lovely Rhine Promenade which we wouldn't have found had Robert not told us! It's also a 5-10 minute walk from a bakery and small supermarket. The bus stop is also by the supermarket and buses come every 15 minutes and take 5 minutes to go to town/train station but you can easily walk in from the house in about 15-20 mins. We would definitely recommend staying here and would stay again if we're ever back in Konstanz!