Since I live in Mexico just below the border of USA, a lot of words we use are spanglish (words made from spanish and english) and a lot others are just the same (but pronounced as if in spanish), so we say soda, because at the south of USA the sey it that way.
But when you go to a restaurant (or a taqueria for that purpose) if you want a cola drink you say the brand (Coca cola or Pepsi), and if you want some other, like orange or strawberry, you say it generally speaking unless you really like a brand (that is not that common), so you ussually ask for a orange soda or strawberry soda ("soda de naranja o soda de fresa"). Here no one serves Dr. Pepper and such (and I damn all for that), but when you buy it at a shop just call it by its name.
At the other hand, to the center of the country they´re not called soda, they´re called "refrescos" ("refreshers"), and for cutting it "chescos".
Nobody says coke (here they say coca, but they´re refering to a cola beverage, and it´s almost not used as much).