It's really a no-brainer: If you use mongo as your backend, this gives you free credits to run fully managed mongo as a service. Takes the pain out of install and ops of the database, freeing you to focus on product and applications.
Pros:Leave the Ops part and DBA to the experts, focus on your product.
Cons:You may get addicted to "free", forgetting that value has it's price. Not currently offered on Azure.
ShufflUp