Best SPF Implementation

[Jason C. Wells]

Which of the ports provides the best SPF implementation for FreeBSD 
running sendmail? 

I messed around with SPF when it was still in it's infancy.  There seem 
to be more choices now.  I value ease of use if that is a useful 
discrimination.  I really need to add something to spamassasin to 
prevent receiving the spam in the first place.  I hate spending time on 
this but these guys are killing me.

Thanks,
Jason C. Wells