Mark, you and I know someone who has been there (allegedly). No, not me.
Supposed to be really, really good.
When I was in college I had a buddy with a friend who lived next to the reservoir, so we went snorkeling (obviously illegal). The biggest snapping turtles you have ever seen.
I live near the Quabbin, and though it is less restrictive it still sucks. And yes there is good stuff there as well, though I have never climbed in the Quabbin, just checked it out.