The best replacement for apc is cyberpower.

The best alternatives to apc are rated as following:
★★★★★  cyberpower
★★★★  upc
★★★★  memcached
★★★  xcache
★★★  tripp lite
★★★  nudie
★★  mpc
★★  apcu
★  adc
★  eaccelerator
★  upc fiber
★  acne
★  tripplite
★  eaton
★  belkin
★  full frame
★  opcache
★  varnish
★  drg
★  panamax
★  unbranded
  3sixteen
  apg
  pdp
  liebert
  belkin surge protector
  launchpad
  memcache
  zend opcache
  belkin ups
  nacc
  powerware
  master airscrew
  zend
  asc
  tpc
  cpt
  luminous
  microtek
  sc pc

Your alternative for apc is not listed? Suggest!
Speaking about apc, one probably shouldn't forget about egd.

Other search terms related to apc and their ratings are:
★★★★★ egd
★★★★★ php-fpm
★★★ fastcgi
★★★ erbe
★★ obasanjo
★★ php 5.4
★ zend optimizer
zend
You have in mind a companion for apc and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of apc in all years. Click on graph for more.
apc
cyberpower
upc