RBL datafeeds free or paid for ?

This isnt a Cpanel specific question but since we are suddenly seeing ALOT of posts regarding spam I would like to bring up the question of what everyone is doing for reverse dns black lists / RBL's, etc.. like ORDB.org, Spamhaus, etc..

We run many servers and found that once we enabled RBL checking in our servers we saw a tremendous drop in incoming spam. It wasnt a cure-all but it sure did help ALOT.

I am concerned however that as we grow we will be using these services more and more and I was wondering if anyone here has switched from the usual free lookups to a paid datafeed.

Is there a point when the RBL service providers will cut you off because of traffic/load on their servers?. Anyone here have ALOT of servers which do tens or hundreds of thousands of requests daily with the free lookups or have you switched to a paid feed.

If you use a paid feed like Spamhaus what do you pay and do you have any problems with it ?.

Thanks.

 

We found that spamcop will list just about anybody's complaint which we have had alot of complaints about. Spamhaus has a pay-for feed service for ISPs where you get their feed every 30 minutes via rsync.