do you use SPF TXT RRs? (RFC4408)

Mon Oct 4 16:47:52 UTC 2010

A partner had a security audit done on their site.  The report said they were at risk of a DoS due to the fact they didn't have a SPF record.   

I commented to his team that the SPF idea has yet to see anything near mass deployment and of the millions of emails leaving our environment yearly,  I doubt any of them have ever been dropped due to us not having an SPF record in our DNS.  When a client's email doesn't arrive somewhere,  we will hear about it quickly,  and its investigated/reported upon.      I'm not opposed to putting one in our DNS,  and probably will now - for completeness/best practice sake..  

how many of you are using SPF records?  Do you have an opinion on their use/non use of?

take care,
greg