We stayed in this hotel over a long weekend at the beginning of May. The weather was still really cold, but Spring was in the area and the tulips were beautiful. The hotel room was pretty simple, but I have rated four stars simply for the location and views - IF you choose a lake view room of course. The breakfast was included, but was really disappointing. There was mouldy bread, and not much of a choice of nice cooked food. Only cereals, fruit, cold meats and cheese, etc. But I guess my expectations were higher. The room itself was clean, and basic, all we needed. I would not want to stay in peak summer heat though - there is no air conditioner, or bar fridge - something else we like to have when staying in a hotel. The bed was comfy, and bathroom clean and well-fitted. There is no tea/coffee facility in the room - this seems to be the norm in German hotels.
The hotel has bikes you can rent to ride around the area. The location of this hotel is perfect and really stunning. You can catch train to Lindau, were you can get a boat to Bregenz etc. The lady at reception was very helpful showing us the map and boat times etc. The hotel is only a short walk away from the train station and one of the piers. We took a boat trip to Constance and were very glad we had selected our hotel in Langenargen rather than Constance itself. The little town of Langenargen has some restaurants, we loved the Italian one for dinner. There are ice cream shops and a few other shops if you need any essentials. There is boat dock only a minute or two's walk from the hotel where you can rent boats and peddle boats.