The USO is a true miltary grade, SHTF scope while the Vortex only serves as a gun game scope. The Vortex has a BDC only reticle and weighs 24 ox. without mount. While it offers good clarity and a daylight visible dot, had Vortex put in a capable ranging reticle, reduced the weight, and offered it in black as well, they would have had a solid offering.
You have to decide the best scope to fit your needs.
gun games - Vortex
SHTF use and durability - USO