Do you know which area you will be moving to? Tucson is not super big but very spread out and I agree, it can be hit and miss with good areas but avoid the areas already mentioned and you are going to do great.
We are moving in a few weeks and have only been here for 2 years. Hard to leave as there are alot of parks, rec areas and libraries that have great play groups to join! The Tucson children's museum is AWESOME, along with the Reid Park Zoo~both very affordable and child friendly. They were a staple when we first moved here.
It does get a little bit of snow in the winter so that was a surprise to us!! Just wanted to add that and hope you enjoy it here!!