Vantaggi
The USO uses its mission as a shield for misdeeds and poor employee culture. That said, sure, it's noble to say "I help support the military" just like a teacher, police officer and nurse can feel validated in their choice of career--they're helping people in public service of sorts, too, so the USO operates under a guise of "doing good."
Svantaggi
However, the USO has long been irrelevant. Sure, they post pics of happy soldiers/airmen/sailors, etc. whom they asked to pose for their social media PR screen grabs. But the bingo sessions, stale coffee, and lame little care packages of the 21st century pale in comparison to when they brought entertainment to the troops stationed overseas who had limited contact with their families. Everyone has a smart phone now so there isn't the same need for connection that the organization once fostered in hard-to-reach areas. Plus, the pay is marginal unless you're the top brass (who makes more than the president of the US, btw), they do same-day no-notice layoffs every 2-3 years, and generally lack innovation in a changing world.