I've spoken to a few who are still "in" and I'm hearing the same story over and over: A lot of JWs have doubts and there are a some circles where they share their doubts among each other.
Sadly, I suspect that the vast majority of JWs have doubts but are too scared to tell any other JWs for fear of being turned in to the elders. The situation reminds me of the German Stasi. http://en.wikipedia.org/wiki/Stasi