Hi Rob,
I saw you left bad review also to other great plugin (not ours) “killed site on uninstall” one week ago. That plugin has 3.500 5 stars! Wow!
If you go to our support site we can try run a debug on your site and find what is wrong with yours sites and hosting.
Sometimes is low wp memory limit, your hosting configuration and a lot more things, malwares included.
Anyway, request support before left bad review and install only on one small site to test one plugin before install in 5 sites.
Cheers,
Bill