THIS IS NOT A HOTEL
The first thing to realise about A&O Berlin Mitte is that it is NOT a hotel - this is a youth hostel, despite the name of the outfit. You should therefore be prepared for lots of noise, running around in corridors overnight, slamming doors, and "hilarious" games of knock-down-ginger around midnight.
And if you can handle literally hundreds of loud teenagers first thing in the morning, the breakfast buffet is reasonably good value too.
That said, the family rooms are spacious and clean, and the beds are very comfortable. The shower cubicle is quite small, but having a separate toilet was very handy.
If it wasn't for the noise, this would be the perfect budget base for exploring Berlin.