Boclean was a paid for product before Comodo purchased the company and Comodo made the decision to offer the product free of charge as part of their policy of providing free security software to create trust online.
Also: does the fact that a product is paid for mean it is better than one that is free: compare Comodo firewall 3 against any other firewall - it is the best there is and it is free. Comodo have invested huge amounts of money into development of security products. It is worth reading this:
http://www.comodo.com/boclean/boclean.htmlTo quote a snippet from the Comodo Website regarding Boclean:
"We have located and studied over 1,000,000 malware programs and new ones are appearing daily. The vast majority of them are modifications to older, existing malware. We only count unique malware in our "effectiveness count" and do not include renamed, repacked or variant malware in our listings. BOClean will simply detect those, eliminating user worry over so many "zero-day" warnings seen from other software manufacturers that turn out to be a repack or variant."
CAV and CAVS are the same though I think CAVS is the correct term - Comodo Antivirus and Antispyware. I think CAVS 3 will be very good once it is finished.
