The main problem with the AWS ecosystem is you generally need to code against it directly. Much of the OSS stuff is designed to have a much more drop-in feeling, especially if you are going with stuff like Spring Cloud etc to abstract over things for you.

If you can choose an option that is going to be way less work even if it's "more complex" that is often the right choice as long as you understand what that complexity is and can pierce through the covers if necessary.