Unfortunately, there are not many perks involved with being a committer. Recognition as a competent software engineer is probably the only thing that will be of benefit in the long run. However, there are at least some perks:
As a committer, you may apply to Jun Kuriyama <kuriyama@FreeBSD.org> for direct access
to cvsup-master.FreeBSD.org, providing the public key
output from cvpasswd yourusername@FreeBSD.org freefall.FreeBSD.org.
Please note: you must specify freefall.FreeBSD.org on the
cvpasswd command line even though the actual server
is cvsup-master. Access to cvsup-master should not be overused as it is a busy
machine.
FreeBSD committers can get a free 4-CD or DVD set at conferences from FreeBSD Mall, Inc.. The sets are no longer available as a subscription due to the high shipment costs to countries outside the USA.
FreeBSD developers may request a cloaked hostmask for their account on the
Freenode IRC network in the form of freebsd/developer/freefall name or freebsd/developer/NickServ name.
To request a cloak, send an email to Eitan Adler <eadler@FreeBSD.org> with your
requested hostmask and NickServ account name.