Hey Jon, good question. Sometimes when English is not the native language sentences can sound a little akward or spelling mistakes pop up. It does depend on who you get and what you're after - you always get what you pay for imo.
If you run out of luck with the Filipino outsourcing hit me up and I would be more than happy to help you out. I hear struggling Aussie students also do a pretty good job and come pretty cheap ;)
(and yes, I've had industry experience in both affiliate management and writing for all sorts of adult sites
)