There are some problems with mfunc that are fairly major security threats.
I use W3TC and there is an update in the last week fixing this:
WordPress › W3 Total Cache « WordPress Plugins
Update WP Super Cache and W3TC Immediately – Remote Code Execution Vulnerability Disclosed | Sucuri Blog
I use W3TC and there is an update in the last week fixing this:
WordPress › W3 Total Cache « WordPress Plugins
Update WP Super Cache and W3TC Immediately – Remote Code Execution Vulnerability Disclosed | Sucuri Blog