Chateau Kotera is an interesting place. It definitely has a great potential, but it needs some serious investment. If you are going there, you should know that there're 2 parts: the old villa, and a new building called "Orangery".
Architecture of the old part is great, but one can immediately see that some renovation is needed. The same thing can be said about the rooms. We have booked a room in this part, but then refused to stay here, because there were some annoying details like damaged carpet and not so great bathroom.
We moved to a room in Orangery, which was in a way better shape. Although it is lacking the atmosphere of the rooms in the old villa, it seemed to me as a better place to stay. Which is sad, because the old part definitely has its spirit.
Great thing about this place is the restaurant. Forget that you can get a decent meal in Kutna Hora, which is really close. Here it is something completely different. The restaurant has a nice interior, and quality of the meal is solid (but not great, compared to what you can get for the same price in Prague). Prices of wines are a bit steep, but that was the only issue I had.
And beware during checkout - if you don't manage to make it to the breakfast (which we never asked for during the reservation), they still want to charge you for it. Ugly habit.
I would definitely like to come back some day, mostly because of the restaurant. And if they will invest some money into renovation of the old villa, I'll be happy to sleep there too...