This plugin is a total mess. It tries to do far too much now and does nothing right any more. Unfortunately, 1 star is too much for it.
I have no clue what the developer of this plugin is doing, but I'll never pay him after I've seen how much he broke the plugin, not even 10 cents.
There are known fixes to various bugs of the plugin, but the developer is too busy adding useless features instead of making sure sites won't be broken when the users update plugins.
The developer should stop advertising their services in the plugin. I wouldn't trust them to watch my cat for 2 minutes.
I've updated and checked the websites were loading just fine after clearing the cache. I've found two of them missing their CSS styling about 8 hours later. Another website was showing some random garbled characters, most likely due to broken / incorrect gzipping caused by w3 total cache.
Good riddance, W3 total cache. You're dead to me.
update: if your website is at /blog/ or something like that, 0.9.2.7+ won't have working minification