This is the question we get more than any other. The answer comes down to two things: how much sun your yard gets and how much foot traffic it takes.
Bermuda: The Sun Lover
Bermuda needs full sun. At least 6 to 8 hours of direct sunlight per day. In shade, it thins out, gets leggy, and eventually dies. If your yard has mature trees casting afternoon shade, Bermuda is not going to work in those spots.
What Bermuda does well: handles foot traffic, recovers from damage fast, tolerates drought better than St. Augustine, grows thick enough to crowd out most weeds, and costs less to install. Tifway 419 is the standard Bermuda variety in DFW and it looks great when maintained properly.
The downsides: it goes dormant (brown) from November through February. It's aggressive and will invade your flowerbeds, your neighbor's yard, and every crack in your driveway if you don't edge regularly. And it needs full sun. No exceptions.
St. Augustine: The Shade Tolerant Option
St. Augustine handles partial shade. 4 to 6 hours of sun is enough. This makes it the default choice for yards with large oak trees or north-facing exposures that don't get full afternoon sun.
St. Augustine has a wider blade and a darker green color than Bermuda. Some people just prefer the look. It stays green a bit longer into fall and greens up later in spring.
The downsides: it's more expensive to install, needs more water than Bermuda, doesn't handle heavy foot traffic well, and is vulnerable to chinch bugs (a devastating pest in DFW that can kill a St. Augustine lawn in weeks). It also doesn't recover from damage as quickly. If a section dies, you're patching it with sod rather than waiting for it to fill back in on its own.
Head-to-Head Comparison
Sun requirement: Bermuda needs 6+ hours, St. Augustine handles 4+ hours. Drought tolerance: Bermuda is better. Foot traffic: Bermuda wins easily. Shade performance: St. Augustine by a mile. Water needs: Bermuda needs less. Pest vulnerability: St. Augustine is more susceptible to chinch bugs. Winter appearance: both go brown, Bermuda earlier. Recovery from damage: Bermuda fills in faster. Cost per square foot: Bermuda is cheaper ($0.30 to $0.45 vs $0.40 to $0.60 for St. Augustine).
What We Usually Recommend
Most DFW yards aren't 100% sun or 100% shade. The front yard gets full sun. The backyard has a big oak tree. So we often install both: Bermuda in the sunny areas and St. Augustine under the trees. The two grasses look different (Bermuda is finer-textured, St. Augustine is wider-bladed) but from a distance it works fine, and each grass thrives in its ideal conditions.
The third option nobody talks about: Zoysia. It's shade-tolerant like St. Augustine but handles foot traffic like Bermuda. It grows slowly (less mowing), creates a dense mat that resists weeds, and looks good year-round. The catch: it's the most expensive option and takes longer to establish. But for homeowners who want one grass type for the whole yard without babysitting it, Zoysia is worth considering.
Whatever you choose, soil prep matters more than grass type. We till compost into DFW clay before every sod installation. It improves drainage, gives the roots something to grab onto, and makes a bigger difference in the long run than which variety you pick.