I would imagine that with Emory’s association with the CDC, Emory should be pretty well known to physicians and administrators around the world.
The schools are so different that you should just choose according to fit, since they will cost the same.
Generally speaking, international rankings favor research universities that spend a lot on research and whose faculty win awards and publish texts. International rankings don’t really tend to care about average class sizes or student/prof interaction. The former would favor UCLA; the latter, Emory.