Typically, you see the logo before you get into the actual car. I would say you can tell by the shape, but some brands share too much in the looks department (cough Kia/Hyundai).
Nowadays Kia and Hyundai target different segments, but quality is about the same. Kia also does more region-specific models, like the Ceed in Europe and the Telluride in US, while Hyundai seems to have a more global strategy where they choose what to sell from a portfolio of global models.
I assume Kia is South Korea’s lower end offering, Hyundai is their mid tier offering, and Genesis is their luxury offering.