Beyond that, it seems that they've spent the time to integrate ES with IAM, so having the ability to grant fine-grained access to ES using IAM policies will be

Beyond that, it seems that they've spent the time to integrate ES with IAM, so having the ability to grant fine-grained access to ES using IAM policies will be a big plus for some people. We're currently using Found to host our ES index and we had to come up with some pretty creative solutions to avoid embedding the auth credentials in our applications that need access to ES. With the new service, we'd simply setup the correct IAM policies for ES and assign the proper IAM roles to the instances running our application and be done.