I've been a Quicken user since version 1.0. Between MS Money and Quicken, it's 6 of one, half a dozen of the other. Whichever one you use first is the one you'll like the best, usually. Other than that, there is no difference between them to amount to anything. Both applications allow you to download transaction from your online banking accounts, as well as interface with tax preparation software.
I prefer Quicken, mainly because it's the one I used first, and I also use Quickbooks Pro, which interfaces natively with Quicken.
My big problem with regard to MS Money (2007) is that it requires a "Windows Live ID" (used to be called a Passport ID) in order to connect to and communicate with your online accounts. The Windows Live services are many, including Windows Live Mail (the Hotmail upgrade), as well as mapping, scheduling, instant messaging, managing RSS feeds, bookmarking, and vertical search.
If you use a Windows Live ID for these, as well as for communicating with your financial institution via MS Money, while very convenient and the data transmitted is encrypted, you are literally entrusting your financial data to Microsoft's servers. One slip of the password falling into the wrong hands, and identity theft will have a whole new meaning.