I just found out that
cron has been deprecated in Mac OS X. Why is this, and will it eventually be completely removed from future releases?
With the release of Mac OS 10.4,
The wikipedia article on launchd has a very good summary, extended discussions as well as some great videos and external links for a deeper dive into this decision by Apple.
In a nutshell,
When: 29 April 2005 (When OS X Tiger was released for sale)
There's nothing from preventing us all from using launchd to start cron now on Tiger, Leopard or Snow Leopard.
Should future Apple stop shipping
I don't even know if cron has been deprecated.
Daemons and Services Programming Guide says that it has been deprecated though:
crontab is also required by POSIX, and OS X is supposed to be SUS compliant.
In any case, cron won't probably stop working any time soon, and I don't know if it can be said to be slower or less secure than launchd. The cron process should use almost no CPU time or memory. Some advantages of using or learning cron are that it is also available on other platforms, and the configuration format is simpler.