Please be specific about the areas of Houston and Dallas. These r huge cities and there r undesirable areasin each of these cities. You have to consider the location of your work, distance from airport (if u frequently travelling), etc.
Austin is smaller than Houston and Dallas. It is very nice city with a good mix of liberal and conservatism. It has an educated community and a good strength of acadamicians. The traffic is not bad and crime rates r notbad for even the worst of the areas. The schools are good. Envrionmental beauty is good.
Personally, I think Dallas maybe less polluted than Houston.
Both Dallas and Houston are hubs for big airlines, Dallas for AA and Houston for Continental. Although, Austin has a strong SW and AA presence. Schools r good in Dallas and Houston if you stay in the privileged and mid to upper middle class areas. Please dont use my assesment as the final word since I do not have direct experience with the school system.
My ratings in descending order of preference: Austin, San Antonio, Fort worth, Dallas and suburbs and Houston.
Employment market order (high to low): Houston, Dallas and suburbs, Austin & FW, SA.
Housing cost (low to high) SA, FW, Dallas suburbs, Houston suburbs, Austin, Dallas, Houston.
Education: Austin, Dallas suburbs (like Irving).....dallas/ houston...
Ofcourse, if you are ffrom the subcontinent and survive on similar company, Dallas or Houston will provide that better than the other cities.