If by "experience" you're asking if I have worked at one, then I have no experience.
However, if you mean any dealings whatsoever, then I have a few I would consider valuable.
I know professors who have worked at these firms who have spoken to me in depth about their experiences. I have spoken to other attorneys during the callback process who have worked at these firms, but no longer do. I have interviewed with comparable firms. And last but not least, I have done traditional paper research on these firms, because I seriouly considered working for them.
That being said, perhaps my view is completely skewed because I chose not to work in NY big law, and I am simply defending my own choice not to do so. That's certainly a possibility. Then again, I was simply weighing in on a public inquiry with my own opinion, one which I warned was negative prior to disclosing.
I don't think anyone on this forum, if they actually worked there, would be in a hurry to bash the place that sustains them. And also, they would be subject to the same choice-defense bias that I can be accused of.
That being said, I again, must submit, that these firms will provide negative associate experiences FOR MOST grads across the board. I just feel that way. I am glad they are there, and that people work them, because it reminds me of how I'm not AS miserable AS I COULD BE during rather low moments.