Generator is in a great location in the heart of Berlin, a good place to connect with other travelers from all around, and in general a good option for Mitte.
I did enjoy the shared spaces, especially the cafeteria, which offered spaces to relax and/or work. The reception staff was super helpful and understanding.
I stayed in a 4-room bedroom which did have some issues - the cleanliness of floors and the bathroom could have been improved. I also had issues with the room, especially the light setup (the main light would wake me up every time a room mate would come in). Cleanliness in the room was also an issue, mainly regarding floors and the bathroom.