You can also run PHP as CGI, and I wouldn't be so sure that CGI PHP runs more efficiently than CGI Perl. Basicaly any mod_something is more efficient than CGI something. Also I'm not so sure which one is easier to learn, but this is probably a question of preferences.
--
Someday, people who know how to use computers will rule over
those who don't. And there will be a special name for them:
secretaries. -Dilbert quote