I wanted to share my test results:
I did ab -c 5 -n 100 against a phpinfo() on both Apache & LSWS. Same server, same php.ini, same PHP version, same PHP configure command (besides --with-litespeed, etc.):
Apache mod_php5 average:
Requests per second: 714.29 [#/sec]
Requests per second: 1449.28 [#/sec]
Both have eAccelerator.