New Orleans has better culture and food but Dallas is more safe. Either city you will be staying in the suburbs.
If you choose Nola, invest in some good house insurance. If you choose Dallas, be prepared to spend heavy on gas because that shyt is huge. The metroplex is larger than the state of Rhode Island.
I believe there is no state income tax in Dallas but there are toll roads. The cost of living is way lower in New Orleans though.
I would choose New Orleans.