Houston or Dallas?

Currently in the process of relocating from ND. Have a number of States and cities on my list of potentials, but Texas is consistently #1 for it's affordability, climate, and because I've always wanted to see it. I only have two criteria for which city I move to: low rent, and walkability/public transport. El Paso was the original winner, but I was put off when others pointed out that unless I speak Spanish (I don't), I'll be all but useless in the job market. That leaves me with Dallas and Houston.

Can any Texans vouch for which is easier for someone who doesn't drive to live in? Which one has a better public transport system?