I was using W3TC up until a couple of days ago. The plugin has many great features, but does a poor job halding post pages with comments and the users get annoyed when they post a comment and the page goes blank.

WP-SC is a much better alternative. Much easier to set up and does a better job. I kept the image and browser cache .htaccess rules from W3TC and put the plugin to work. After a full day the stats are looking better and the server load dropped with about 20%:

WP-Cache (1.61MB) » 164 Cached Pages
WP-Super-Cache (170.92MB) » 3834 Cached Pages

Some say Hyper-Cache is better, but i never got it to work properly.