Works great

Dropped it in as described, my APCu was ready, it just works, the apc.php utility shows all the fields it stores to APCu – seems well worth it. Works in parallel with WP-FFPC cache using APCu.
January 2016: Also works with PHP7 and APCu (krakjoe made PHP7 Vn. of APCu the master branch at GitHub already).
In my experience this is better than using Redis: There’s a great Plugin available for Redis object Cache. But the point is, APCu stores it’s data in Shared Memory of a running PHP-FPM process, whilst Redis (and Memcached) must go over a socket or TCP connection to access the data. So APCu must be the fastest way! I also use APCu for ownCloud, works fine there, also.