Im doing research on which one of these to use and I can\'t really find one that stands out. Eaccelerator is faster than APC, but APC is better maintained. Xcache is faster
If you want PHP file caching only, you can use eAccelerator directly. Very easy to install and configure, and give great results.
But too bad, they removed the eaccelerator_put and eaccelerator_put from the latest version 0.9.6.