Texas is Awesome!!!
I'm from Austin but I go to school in San Antonio (which I noticed was not on your list :-( ) Anyway, Texas is great. The people here are very friendly. I'm not sure what your image of our state is but a lot of people tend to focus on the wild west or small town image. Those are both real and you can definitely find them if that's what your looking for. There are quite a few ranches and cute little towns but we also have the big cities. The climate is great here (Houston can be more humid than the rest of the state though). It is pretty mild year round but summers are HOT! It's been getting up to about 115 degrees the past few summers. (Thank goodness for A/C!) I've been to all the major cities; I was born near Houston so I'm most familiar with that area after Austin. All the cities you mentioned are great; you should look into San Antonio too because its a great place to live. Geez, I sound like a travel brouchure for Texas
Oh and by the way, we do say "ya'll" and some people do have the Texas twang but the accents vary depending on the part of the state. Hope this helped! Let me know if you have any other questions