On the other hand, for the next step up, e.g. small production services with spiky workloads, it looks great, assuming I've read the product details correctly.

On the other hand, for the next step up, e.g. small production services with spiky workloads, it looks great, assuming I've read the product details correctly. Case in point, I have one service that doesn't usually need a lot of DB grunt, but has occasionally spiky and unpredictable read-heavy data extractions. It runs happily on a multi-AZ pair of db.t2.small instances, for which we currently pay $0.104/hr (ap-southeast-2). Frankly it could mostly run on a db.t2.micro but we occasionally need the headroom of the bigger instance and the availability of multi-AZ. So when Serverless Aurora comes here it'd be a shoo-in, being both cheaper and more scaleable, and with more replicas to boot.