I installed WP Optimize on a client's site, ran the plug in and it totally erased that site and two others belonging to the client (that I do not perform work on).
I have searched and found no one else online reporting a similar issue.
What I know:
1) According to the hoster, all three sites were on the same server with Amazon.
2)All of the data is gone and the guy who built the database has had to rebuild it.
3) I use this plugin for many other clients and on personal sites without issues.