You'd get a lot more blocked just by using some well chosen blocklists.
My recommendations are:
sbl.spamhaus.org cbl.abuseat.org opm.blitzed.org zombie.dnsbl.sorbs.net relays.ordb.org list.dsbl.org http.dnsbl.sorbs.net socks.dnsbl.sorbs.net misc.dnsbl.sorbs.net smtp.dnsbl.sorbs.net web.dnsbl.sorbs.net dul.dnsbl.sorbs.net
That takes out a lot of the spam (they are listed in order of preference in case you want to trim off ones that look dodgy).
Except these also have a good chance of blocking legitamate mail. I've had several bad experiences with blocklists of this type who blocked my mail simply because I was at the same ISP as a spammer. This guerilla warfare stuff creates too many innocent casualties.
It's possible that the services that you mentioned don't employ bad listing tactics, but you'd still be relying on somebody else's judgement on who to block. I would rather keep my own blocklist, which I can trust.
Andy Ruse
