I've been to Brazil many times and I've never even seen a Pepsi bottle, whereas Coca-Cola seems to be part of the culture there even moreso than in the States.
It varies drastically depending on the state. In São Paulo it is pretty common to see PepsiCo's presence in both sodas and snacks (Elma Chips), but people often prefer Coca Cola.
Mountain Dew isn't here, but Pepsi Twist (some hybrid in between Pepsi and Montain Dew) is sold regularly.
Also, it is fun to notice that I've had both Pepsi and Coca Cola with very different flavors depending on the state.
AmBev is also pretty popular with Guaraná Antarctica. Coca cola tried to introduce its own Guarana soda two times (Taí and Kuat) and mostly failed.
If you consider their parent companies, you can say Pepsi is larger than Coca-Cola in Brazil, since the Pepsi brand here is owned by AB-InBev. But Pepsi definitely did not win the Cola War.
