This is hairy! In case the `\Memcache` class is missing it will crash. In case `addServer` doesn't work as it's supposed to, it will crash. In case `getExtendedStats()` doesn't work as expected, you'll get a php notice (because $array[] will be missing a key). 

I believe it should start with checking if MemCache is available at all and throw a Failure otherwise... then it should be able to work around problems with incompatible versions and data coming from methods...