The ability to deploy with minimal configuration of your applications - all done via API's.
This is very important when you're deploying new versions without downtime! I wish there was an easier way to add more fields using metadata instead adding them one by one through their web gui (which isn't that easy). You can create custom tags but it requires some experience before being able to use this feature effectively because its not intuitive at first glance what exactly will be used from each field/tag combination. We are solving scalability issues across different clouds within our infrastructure while maintaining control over where we want things deployed too.