Do you guys see a performance hit when using so many RBL's? I'm just using Spamcop, and since it is catching over 80% of inbound SPAM (with SA getting about 99% of the rest), I decided not to add another.
I have no idea of the lookup time needed to check a spam against an RBL, but considering some of you are using 4+ I would assume its not bad??
Thanks,
Geoffrey