I hired a woman once from the Philippines to do lead gen for $5/hr + bonus. She was better than half of the native English speakers.
English is native to the Philippines as well.
They speak quite good English there. The radio stations are in English. Friends in big cities talk to each other in English. Etc.
The biggest differences I've seen: Filipinos speak with a Filipino accent (bad for cold calling). In written communication they're a lot worse at grammar and sentence structure. Lastly, they love using the word "sir".
However, that doesn't mean the whole population is that way.
If you're paying $5 per hour, then you tap into the top 10% of assistant talent in that country. In my opinion, I'd take the top 10% of the Philippines over the average $12/hour American any day.