STAB Facade with Guts
More Speed then Braviary
Other coverage options/pivoting in U-turn, Pursuit, Steel Wing
STAB Boomburst with Scrappy
Less attack to start with, wasting a turn to use Protect to get a Guts boost
Worse coverage options
Very good STAB attacks in Return and Brave Bird
More useful coverage like Superpower, Rock Slide, etc.
Pretty bulky, takes advantage of Substitute + Bulk Up
Pivoting with U-Turn
Better at using Roost
Slower than Swellow
Can't take advantage of Sheer Force
Honestly I think Braviary is better. It can't use Sheer Force + Life Orb because it doesn't have that good of attacks that take advantage of Sheer Force, so Defiant is usually better. Braviary has a lot more pros to use it, but it's your choice.