Difference between APC & Memcached and how both can be used for cache bins
APCu
Does not share the cache with other servers but is faster.   

Memcached
Can be shared with other servers and is slower.

If you have 2 or more web servers (apache/nginx) for the same Drupal site you'll want Memcached. If you are running on a single machine then APCu will be the quickest. You'll want OPcache turned on no matter what.

LCache is a module designed to fix the issues with using APCu in a 2 or more web server environment.