"The release of the Microsoft Safety Scanner has resulted in confusion about the available anti-malware tools provided by Microsoft and questions about when they should be used. 

Before answering the questions, let's take a closer look at the products available from Microsoft."

Full read from Security Garden here:

Understanding Microsoft Anti-Malware Software

This is a nice review of the various MS security products currently offered, of interest to anyone using MSE, Windows Defender, the Malicious Software Removal Tool (MSRT), Microsoft Forefront, or who wants to learn about Microsoft Safety Scanner, a new free on-demand scanner and malware removal program.

I downloaded the latter (a whopping 68.7 MB!) and ran a quick scan- took only about 6 minutes. It's a very simple and intuitive program, with virtually nothing to configure. It provides no real-time protection, and is meant to supplement, not replace, your resident anti-virus program. It does not update, and is really only a one-time 2nd opinion scanner, since definitions change daily. It expires after 10 days, at which time you would have to download the latest copy. No need to uninstall the old copy- just delete it.

It did not conflict with any of my other security programs.

Another review of it is here:
http://www.softpedia.com/reviews/windows/Microsoft-Safety-Scanner-Review-195411.shtml

I'm not sure I would use this product for routine maintenance, as I'm not sure what options if any are offered when something is detected- (Ignore/quarantine/delete/automatic removal?) A program that big has to run the risk of having false positives.