Moving from AWS to DO will force you to handle a lot more devops/IT stuff to work around network and api reliability issues. So to make that worth it, it'd really depend on how much money you are looking to save and on the IT/devops resources you have available.

AWS may be more expensive, but perhaps instead of migrating away from AWS to another provider, you can start using AWS more efficiently. Most people I've helped out in similar situations were able to reduce their AWS bills between 50-75%.