What I love about the area is the community garden, where you can lease a large size planting area from the city to grow enough food for a family of 4. They have plans to organize areas for children to have their own gardens. It is quite progressive, but does depends on which neighborhood/subdivision you are planning to move to. Rancho El Mirage and Dave Brown are the nicer communities in El MIrage. There are also plans by the city to put in more bike paths and walking paths near Thunderbird Road.
To help with your question, El Mirage has really done a lot in the last few years to provide a more family, friendly city. Some of these improvements include building a new park along El Mirage Rd with playgrounds, ball fields, and even a skate park! There is also a great public golf course in the heart of the city.