The entire southern half of San Antonio (south of 90/10), with few exceptions is ****ty, all the new development has taken place in the northern half for decades.
You basically don't want to live inside 410 (on the southern portion) if you can help it, given a choice.
The 151 area is fairly nice and gets nicer as you approach 1604. Sea World is out in this area.
Marbach is an average area, it's a mix of nice and ****ty houses depending on the area. Stay far away from any area near castroville road and 90.
Alamo heights and terrell hills are bad suggestions, the commute would take you close to an hour each morning.