We stayed here twice on both legs of a long weekend trip to Germany. On our first stay, the air-conditioning in the room made a great deal of noise, but provided no cool air on a very hot July night. We complained to reception, who immediately provided a fan, saying there were no other rooms available. We questioned at checkout the lack of air conditioning, and were offered profuse apologies, saying it would get fixed. On our return trip a few nights later, we had a different room, with the same lack of air conditioning. It appears this hotel does not actually have working air conditioning at all, which was the reason we chose it on a weekend which was likely to be hot.
Apart from this, the WiFi was almost useless (floor 4). The mobile devices couldn't connect at all, our PC with a booster aerial did connect, but it was very slow (maybe 1Mb/s)
On the good side, the rooms were quiet (with the window shut), and breakfast was quite adequate, with eggs and bacon cooked to order.