Ah, it has been a while since we've had one of these OC "dick measuring" contests.
Keep in mind that what one law enforcement agency labels as "the biggest threat," or "the most violent," or "the most sophisticated" often comes down to what they investigate specifically.
In my own opinion, I would certainly agree that the Mexican cartels, like the Colombian cartels before them, are more comparable to the Italian groups and other international OC groups. But even more violent. And here in the U.S. I would agree that the Mexican drug trafficking groups are now the most dangerous, given their dominance of so much of the drug trade from coast to coast.
But more sophisticated or more powerful than the LCN was here in the U.S. at it's peak? Don't think so. The Mexicans don't influence entire political machines or police departments here in the U.S. They don't control national unions or union locals in various parts of the country, by which they can effect everything from interstate trucking to shipping on the eastern seaboard. They don't have a lock on the various illegal rackets and legitimate businesses like the mob has had in the past.