There sure seems to be a lot of misinformation in this thread.
Stay on the north side of Dallas/Ft. Worth and Irving has ghettos?
Weird.
As for Mansfield, my mother, sister and her kids live in South Arlington (360 and south of I-20) but they go to Mansfield Schools. My mom told me she moved to that location in Arlington because she felt Mansfield schools were better than Arlington Schools.
It really all depends on what qualities you are looking for in your community. If you are looking for low Property Taxes, you may want to avoid Dallas and Tarrant County because they are typically higher then most counties because you have to pay for their County Hospitals.