The Hoppegarten Hotel is not in Berlin, and it isn't easily accessible by public transit - whether by car or by taxi+train, it's nearly an hour from the city.
The hotel staff weren't helpful, even by German standards, and the hotel offers no small comforts like toothbrushes or slippers. The corridors of the hotel were very dirty, and so displeased was I that I crushed a ketchup packet on the elevator door before going up to my room at about 5 pm.
The rooms were barren, and make a small town Holiday Inn or Howard Johnson look like a Four Seasons resort by comparison. I image that this must be the most disgusting "four star" hotel in the world. I've traveled extensively and never have I been so displeased with my accommodations.
Since there's absolutely nothing near the hotel, you're more or less forced to go to their restaurant. Suffice to say that the hotel exploits this, and offers nothing less than disgusting food for an outrageous price. Having already spent a week in Berlin, I had become accustomed to bad, overpriced food, but this was so much worse.
The sheets were clean, but they reeked chemical detergent and were incredibly coarse. The rest of the room looked like an office, and didn't appear clean enough to rub with a white cloth.
On my way to checkout, at around 10 am, I noticed that the ketchup was still on the elevator door. I've traveled extensively and eat at restaurants on a daily basis. The Hoppegarten is the worst hotel I've ever been to (outside of the 3rd world) and the dinner I had there was easily the worst food I ate in 2009.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC