What are some alternatives?
When comparing Spamfence.net and BullGuard Spamfilter, you can also consider the following products
Mailwasher - Over 8 million people use MailWasher as their spam filter
Spam Reader - Spam Reader is a free anti-spam add-on for Microsoft Outlook.
Spamihilator - The free Anti-Spam-Filter Spamihilator removes more than 98% of spam mails before they even get into your inbox.
SpamSieve - Save time by adding powerful spam filtering to the e-mail client on your Mac.
POPFile - POPFile classifies email into categories you define.
SPAMfighter - SPAMfighter and Microsoft have built the strongest and most effective anti spam filter for Outlook, Windows Live Mail, Outlook Express & Thunderbird