Ventajas: I was in Berlin for a couple of days on a business trip. Overall, the facility is mediocre. It is clearly old and a little bit rundown, but nothing particularly major. They try to keep it clean, but there is only so much you can do without major updates. Don't get me wrong-the hotel is not dirty, but it has more of a 2 or 3 star hotel level cleanness, definitely not 4. The location is OK. It's a bit further away from the center, but the hotel is literally in front of a U-station, which makes it easier.
Desventajas: My main two issues were with amenities and service.
First, they have the worst wireless I've ever encountered anywhere in the world. Literally that. The connection was poor and kept dropping all the time. It was impossible to get any work done in the room. I could do some in the lobby, but not in my room. Also, weirdly, the terms of wireless service prohibit you to use Skype or IM under the argument of protecting copyright. I am not sure I understood this logic, but I couldn't communicate with my family from there anyway, because of the poor connection. The TV also didn't work very well. The few channels in English they have kept disconnecting.
Second, the hotel staff, while not rude or anything, was very unwelcoming and not helpful at all. For example, I arrived pretty early and although I did not expect them to have a room for me at that hour, I hoped to use that time to do some work in the lobby. It turns out, you cannot access their wireless without a code and they will not issue a code unless you have a key to your room. They did check me in on arrival, but since the room was not ready I couldn't use the wireless even in the lobby. Why? Nobody gave me a reason, other than this is how things work in their hotel. The staff were not ready to do anything to help. Another example, when I learned couldn't use the internet in my room, I asked the front desk for instructions for getting to some place. Getting those instructions was like pulling teeth - I had to guide the front desk person through the process of looking for commute instructions online all while she does everything to show me that she is doing this unwillingly. Finally, I needed a band-aid at some point. Of course they did not have any.
Honestly, I wouldn't mind most of it, but for what they charge and for the reviews I expected more. I will avoid this hotel in future. There are other options in their price range.