Oh, that's interesting; I instinctively pronounced it poh-NEE-tah...but man, not in a thousand years had I guessed it's GAR-i-dose.

Frankly, I'm the worst person in the world to ask for pronunciation (foreigner with good grammar but limited auditive and replicative skills), but since there doesn't seem to be consensus among the new-gen Pokémon GO players, I wouldn't worry -- until some old-skool Trainer comes along to correct you. :)