Something else people should know: AWS ES is on the Internet. You can't deploy it to a vpc yet, and you can only lock it down using IAM, which may or may not be good enough for your use-case.
For those that prefer the ease provided by AWS ES Service, consider Elastic Cloud, which affords most of the same capabilities but is run by Elastic themselves (it was previously known as Found, which Elastic purchased a few years ago). There's also an Enterprise offering. If you're looking for a hosted Elasticsearch solution, it's probably better than what AWS is offering. Side note: they update about as often as elastic releases, whereas AWS ES is consistently behind.
For those that prefer the ease provided by AWS ES Service, consider Elastic Cloud, which affords most of the same capabilities but is run by Elastic themselves (it was previously known as Found, which Elastic purchased a few years ago). There's also an Enterprise offering. If you're looking for a hosted Elasticsearch solution, it's probably better than what AWS is offering. Side note: they update about as often as elastic releases, whereas AWS ES is consistently behind.