A side benefit has been a spam filtering service that I have slowly ratched up from it's 10 levels to near level 1 to 2 now (have to check) since I have learned to trust it so explicitly.
At the same time I have been sending my spam to SPAMCOP, a great blacklist service (among others). I just discovered (as needled on from this thread) that my great POBOX.com service is now tied to SPAMCOP and a lot of other black list services (Spamhaus, MailPolice, Not Just Another Bogus List, etc.), as well as other outright blocking abilities (e.g. don't send me anything from Nigeria, etc.)
It has greatly expanded it's spam prevention services so I have just turned it all on. And all for $15 a year, for three 'logical' addresses pointed at one physical. More logicals are available at 3 for $7.
I have been shopping all sorts of tools but now that my existing tool has just been upgraded tremendously, I am quite hopeful that I will have the best of all worlds with POBOX.com.
Hmmm .. that last line about "my existing tool" sounds like I have been reading too much of the spam that HAS gotten through!! ;-)