The lobby and the rooms are very stylish. The dorms (as i have experiences them) are standard.
At night it can be really loud.
You will meat a lot of interesting people in the 6 or 8 person dorms.
You will meet people from all over the world here.
The lockers in the dorms are mostly useless, unless you know the guys you sre sharing the room with, don't forget to bring a lock or consider renting one of the lockers at the basement.
If you want to visit Berlin for a short time irs perfect, because its near the center and really affordable.