How are Warsaw and Krakov for families with children?
I think Warsaw's great. Plenty of green spaces, lots of child-friendly environments, and it's pretty easy - if you choose - to find yourself living in a community of similarly-aged kids where they all look out for one another.
The only downside I can think of is navigating stuff like vaccinations, doctors, and general bureaucracy. The majority you'll be fine with, but some working Polish - and having Polish friends - will be helpful as English is in short supply in some vital areas.
In fact, they're bad enough that I actively campaign against them.
Whoops, turned into a rant there by accident, sorry about that :)