Great question. In recent years, I would say it has been more beneficial to Latin America, this being in part because for so many years previous, it was so imbalanced in favor of the United States and its business interests.
In nations such as Venezuela and Bolivia, which have had populist revolutions in favor of Evo Morales and Hugo Chavez, they have nationalized key industries in their oil and gas sectors, meaning more dollars are directed towards their own economies as opposed to being exported overseas. This is controversial, of course, because it costs large companies a lot of money and these companies have powerful friends in Washington and elsewhere.
Where investments haven't largely changed is in agriculture, as land reform in Latin American countries has been quite rare, and large landowners, backed by the US, produce a lot of food and profit for US investors.
Yes, there are many Latin American countries that have attracted the interest of US companies. Companies are buying land and resources from many of the more stable countries. At the same time, the unstable countries like Mexico are seeing a decrease in US interest, as companies try to avoid losses due to drug cartel violence.