I'm confused, are mexicans the worst or are cubans?
Really depends. I'd say Mexicans in parts of the Southwest can be hostile if they have gang ties or just a numbers advantage in general. White Cubans in Miami can be very racist but, as some Miami brehs pointed out in other threads, the racism is more systemic, political, and economic based than tied to hostility, competition, and gang violence.
A Black man is safer in Hialeah than East LA but he won't get job opportunities in either city.
In the East Coast, though, neither Mexicans or Cubans seem to be a problem. Mexicans are quiet and keep to themselves. And they tend to the friendly "Paisa"/"Mojado" types that look fully Native American.
Cubans in NYC tend to be Black or Afro-Latino similar to Panamanians and Hondurans in NYC but Jersey has a lot of White ones. White Cubans in NJ are no where near as bad as the ones in Miami. I never heard of anyone having problems with them out there.
That's just speaking for the American ones though. Funnily enough, Mexico itself is very friendly towards AADOS expats and Haitian refugees and Cuba is similarly accepting of AADOS and Afro-Cubans have a heavy presence and cultural influence there. They tend to look down on their American counterparts too lol.