multi-container docker deploys actually launch ecs for you.  so its basically cloudformation+ecs, removing the step of configuring autoscaling groups and adding some management stuff on top.  Also, it existed before ecs services existed i think, so it handled all the elb stuff.  i found version management much nicer in beanstalk, string versions instead of auto-increment revisions, enhanced monitoring is better than what you get out of the box with ecs, but a second system of things that could go wrong, now just using ecs services always