I have used the paid version of Spamcop for many years and am extremely happy with it. At least 80% of the spam I receive is blocked, which is extremely helpful since my e-mail address is public knowledge. You do have to tweek the filter, selecting various parameters and which blacklists you want consulted. In this way the sensitivity can be increased or decreased. This might be difficult for people who are not computer literate, but the improvement in service is well worth the effort.