It has done more bad than good to some servers of ours.
Basically there's an high chance the minify will screw your blog over.
Even emptying the caches, v 0.9.3 may cause jquery to not get loaded and affect the rendering. Those with responsive themes like Montezuma basically get a blank page (content is still there, if you select you see the writings are still there, just white on white).
Disabling minify immediately restores the website.
Another issue comes directly in the minify window. Some options that may be disabled, return enabled after you save the settings. Furthermore, invoking the helper popup to get the list of minification candidates (JS and CSS) usually results in it being showed for 2-3 second and then a redirect to... nothing. W3TC just hangs and stays stuck till you load another page.
Anyone experiencing these issues should revert to 0.9.2.11: that one works much better.