As an anti-spyware, it "may" be, but it is under beta testing so it is early days yet. Best to stay with Spybot , (and be carful what you tell it to delete in future), and also use SpywareBlaster that compliments Spybot.
Also, do you have a firewall? Do you have any anti-virus software? Do you have any anti-adware software?
I just installed it and it found no spyware on my system. Spybot found a dso exploit, and several other things like advertising.com etc. I used it before and my registry went nuts and I had to repartition my harddrive and install xp all over again. I'm not sure whether or not I should try fixing these problems. And if Microsoft antispyware didn't find what spybot found, is it inadequate?