Are there any specific advantages to using the Amazon Android App Store over the Google Android Market? Is the new Amazon Android App Store just another marketplace or are there any specific features or benefits that the Google Android Market doesn't have?
There are a number of differences between the two marketplaces and while "Advantages" may be somewhat subjective there are a few specific features that the Amazon App Store has that the Market place does not.  


Amazon claims to test each app before making them available for download to ensure that "each app works as outlined in [the] product description, does not impair the functionality of the mobile device or put customer data at risk once installed."
They offer one "paid" app for free each day.
Some apps have a "Test Drive" feature on their website that allows you to try the app in a virtualized Android interface in your browser (although I can't seen to find an app that has this feature yet ).
Amazon is employing their recommendation engine to suggest apps you may like based on your purchase history.


It should be noted that at the moment the Amazon App Store only works in the US (unless you are able to use a US Proxy in another country) and the service is blocked on AT&amp;T devices.