Depends. We've had a few apps that we migrated from on-premise to AWS and made it "full-serverless." Here are some of the things we've learned.
* Scalability is real. We have some bursty traffic, sometimes with extreme burst, and we've had no problems scaling to meet that need.
* Our traffic is still predominately during business hours in the U.S. That's an extremely important point - because our site is effectively being used for only 12 hours or so per day. The remainder of the day and on weekends it's unused. We looked at the cost of using EC2 instances and Elastic Beanstalk and the full serverless is still cheaper.
What we've discovered in our cost analysis is if you have a site that's hit 24x7, 7 days per week then you'd be better off hosting on EC2. If your traffic is constant and there's not much variability over time then it may make more sense to host on-prem. In our case we have highly variable traffic during standard business hours. Serverless is the way to go for that scenario.
* Scalability is real. We have some bursty traffic, sometimes with extreme burst, and we've had no problems scaling to meet that need.
* Our traffic is still predominately during business hours in the U.S. That's an extremely important point - because our site is effectively being used for only 12 hours or so per day. The remainder of the day and on weekends it's unused. We looked at the cost of using EC2 instances and Elastic Beanstalk and the full serverless is still cheaper.
What we've discovered in our cost analysis is if you have a site that's hit 24x7, 7 days per week then you'd be better off hosting on EC2. If your traffic is constant and there's not much variability over time then it may make more sense to host on-prem. In our case we have highly variable traffic during standard business hours. Serverless is the way to go for that scenario.