Hi Luiz,
Personally I prefer the US Extended version as it offers many more accents than the PC version, but if you're used to the PC version, switching may be awkward. It's easy to see the differences though; just open the keyboard viewer, press and hold the alt or alt+shift keys and then switch the keyboard layout (probably works best if you have enabled the input menu on the menu bar). The change in behaviour of the various keys is visible in an instant.
Have fun,
Hayo