Speed without compromise indeed! Not that the plugin doesn't seem to do its job well, but i think it would be a good thing for you to warn people that it's not intended for communities, as in; where most people DO log in. Though perhaps your chosen slogan for this plugin is your backup-excuse for when people complain about what i am about to? ;) Changing the settings to allow logged in users to see the cache makes it so that you simply see the logged out page (front welcoming page that asks users to log in) when you log in. And not having that setting activated, it doesn't speed anything up the slightest for logged in users, which W3C certainly does. Couldn't you at least make the plugin aware of the fact that there are two entirely different pages to load on the index page depending on whether the visitor is logged in or not? As this plugin is the most simple of its kind when it comes to configuration, while a plugin like W3C requires a degree in coding to configure properly, W3C at least knows which users that are logged in and otherwise even if you don't bother configuring it.
With that said, is anyone aware of a cache solution for wordpress that is sort of the golden middle-ground? I've tried three of these plugins now and they all cause serious issues. Starting to wonder why WP seems so hard for cache-plugins-makers to figure out.