On the IBuildings blog Cal Evans has taken a look at the Windows caching technology (some recently released) from a management perspective and where it fits in the overall Windows caching toolsets available.
As PHP extends its reach further into corporate networks, IT managers have yet another technology that they have to understand so that they can properly deploy. In many situations, PHP code is being developed that - running on its own - creates a bad user experience because of the nature of the language. [...] Much of this delay, and the user unhappiness that always accompanies it, can be mitigated with the proper opcode caching solution. The list in this article was compiled to help managers understand what their options they have. These are the most popular or recent PHP opcode caching solutions.
He lists three of the more popular choices - the Alternative PHP Cachie, Zend Optimizer+ and the WinCache - touching briefly on what each has to offer.