Stone Oak far to the north and really really crowded and rush hour is a total mess morning and afternoon. Helotes is very nice and affordable but once again very very far north. Commutes from both these places are long.
I am guessing you a military so you need to look at what base you will be working.
The area that is very popular and more convenient is what some of us locals call the "golden rectangle". North of 410, south of 1604, and in-between I10 and I35. This does cover a lot of area but it keeps you more mobile. Get a good map of San Antonio and look at it.
The nicer areas are north central.
We just lost one of our military families on our street this past summer. Really nice family and great kids.
If you want to pm me with a list of areas you are looking I can get a lot more specific.
NEISD is also a good district. I have worked for them and my kids go to school there. But if you are only going to be here a few years and only need daycare/preschool, it really opens up your options of areas.