Well Sunbelt had a the CounterSpy license before MS bought Giant (otherwise they wouldn't have been able to continue to distribute/sell it), so hardly a knock off.
Another point, MS crippled the Giant anti spyware product, by limiting it to XP and above to try and get people to upgrade their OS, 'CounterSpy works with Windows 98SE/Me/2000/XP.'
P.S. I don't use CounterSpy or MS anti-spy (certainly not until it is out of beta).
Thanks for the Spyware Warrior link, but as you say it is getting a little long in the tooth (Oct. 13-15, 2004), even then Giant was well ahead of the field. Yes reviews without what they tested, how they tested, etc. hold less weight than the likes of this test/review. It would be nice to see them repeat it a year down the track.