When we were military we did Space A one time. It is very basic.
We had web seats and were packed in pretty tight. As for the wait, we were lucky in that we got on pretty easy but we could have been almost ready to board and got bumped by active duty personnel, that's the only downside of Space A.
Then again, if you aren't on a tight schedule, you can't beat it for the price. It was only $10 per person for a hop back when we did it, and would have been a couple hundred on a regular flight.
As far as with kids, I don't know about a long flight if they were real young, unless it was like an overnighter and you knew they'd sleep. Older ones you can take stuff to keep them occupied. But - look at most military planes - there aren't windows along the sides, so there's not much looking outside.
Email me private at ____@____.com if you want to get really into this. Also, where in Germany are you going to? I know you're probably flying into Ramstein but where are you ending up at?
Have a great week
R.:)