The free version works well but you'll eventually get lots of spam. I used it on our wedding website that has not been intentionally indexed by Google and is not advertised anywhere. It's a low traffic site with trafic just form the wedding guests but after a few weeks it still got SPAM on it. It was working fine up to this point so I deided to install the PRO version so I could use its CAPTCHA features. I uninstalled the free module and installed the PRO version. The captcha doesn't work as the CAPTCHA box disappears after you hit submit and no messages could be posted as a guest. The avatars show up as balnk even when you turn off avatars. I'm an experienced web developer and I believe I've configured the module correctly. I usually write positive reviews but was very disappointed with the PRO verison. I wouldn't recommend you buy this extension. Use the free on e if you can get away without the spamming.