EAccelerator i found leaves lots of temp files on the server and eventually uses many GBs of space.
APC i have found to be the best for me. However you could always use something like cloudflare.com as a front to your website which caches content, makes things quicker without using much server resource.
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XCache seems to be good choice. Please be noted, no PHP accelerator will work with suPHP.
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APC and Memcached comes under different era and needs custom configuration. If you are looking for PHP opcode cache, APC and Xcache are good choices. Also opcode cache don't work when PHP handler is set to CGI or SuPHP.