Long time lurker looking for advice...

I'm heading to Costa Rica. Would you guys recommend travelling through the US or through Mexico?

US:
-possibility of fingerprinting + photographing at customs
-possibility of body scanner / invasive pat down at security

MEX:
-any safety issues?
-any customs issues? ie fingerprinting, photographing, arbitrary detention, demands for bribes? I don't need a visa.
-do they have body scanners and can you opt out? do they do invasive pat downs?

SJO (Costa Rica):
-any differences in customs coming into the country, or in screening while leaving the country, if you're flying from/to MEX compared to a US airport?

Any advice, especially from those who've been to MEX recently, is appreciated.