It's free for anyone to sign up as reviewer, and costs a minimal membership fee for those who want to post work. And because it's a password-protected site and you're technically posting work-in-progress, you still hold first publication rights. I joined as a reviewer at first to survey the lay of the land and I was astounded by the excellent work being posted and the feedback authors were getting, so I decided to post my own work. I am so ecstatic I did. I've met some amazing writers and reviewers and my work wouldn't be the same without them. They're awesome. Take a peek and see if it's for you.
~ Signing off and sending out cyber hugs