I think there are like two types of Beta the 'grammar-nazi' (which isn't politically correct but there you go) and then the people who help with plot and stuff. I try and use the former rather than the later.
Yup, they're audio books, but fics in there own ways. I've got a couple of fics podficced it's just like OMG I wrote that it's awesome, like being a real author (which I'm not alas, lol!) Please do, as you've heard the lengths that I'd go to, to be able to hear this :-D