My boyfriend used to beta Running Up That Hill for me LOL. I don't really have a beta for any of my other stuff, but as julilly mentioned I'm reading one that's she's writing
When I did have a beta for my stuff in other fandoms, my beta would either never get back to me, or when he did he changed the story so much to the point that it was unrecognizable from what it had been in the beginning.
For the most part now I'll just post my stuff without anyone else giving it the once over. If I'm really unsure about it I'll ask someone to look at it (and actually, I've been doing that a lot more lately, cause my writing is so far out of my box now) but usually I just post without worrying about it too much.
I guess the logical next question to ask have you ever beta read for anyone else? I find I have a really hard time doing that, because either the story is well written and awesome, so I don't have much in the way of comments, or the story is horrible, and I try my best to be honest about that but there's only so much you can improve in a story that you're really uninterested in reading.