When put against AV-Test's "WildList" collection of 3,194 recent, common viruses, bots, and worms, Microsoft Security Essentials detected and removed each and every one of the malware samples. How does this compare to other security products? AV-Test coordinator Andreas Marx notes that "several other [antivirus] scanners are still not able to detect and kill all of these critters yet." In addition, Microsoft Security Essentials put up a perfect score with zero false positives—it didn't flag a single clean file as being malicious.
Wow... sounds like they might actually have a decent product here.