Managed PostgresSQL Database offering AWS vs Azure...

gistfile1.txt

[1] https://aws.amazon.com/rds/aurora/details/postgresql-details/
[2] https://docs.microsoft.com/en-us/azure/postgresql/concepts-high-availability

AWS 
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High Availability and Durability
Instance Monitoring and Repair
Amazon RDS continuously monitors the health of your Amazon Aurora database and underlying EC2 instance. In the event of database failure, Amazon RDS will automatically restart the database and associated processes. Amazon Aurora does not require crash recovery replay of database redo logs, greatly reducing restart times. Amazon Aurora also isolates the database buffer cache from the database process, allowing the cache to survive a database restart.

Multi-AZ Deployments with Aurora Replicas
On instance failure, Amazon Aurora uses RDS Multi-AZ technology to automate failover to one of up to 15 Amazon Aurora Replicas you have created in any of three Availability Zones. If no Amazon Aurora Replicas have been provisioned, in the case of a failure, Amazon RDS will attempt to create a new Amazon Aurora DB instance for you automatically.

Azure
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Internally in Azure, a gateway is used to redirect the connections to the new instance. Upon an interruption, the entire fail-over process typically takes tens of seconds. Since the redirect is handled internally by the gateway, the external connection string remains the same for the client applications.


Which Vendor would you choose? 
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AWS is basically telling you pay for more to have a idling standby node for failover, while Azure is saying we gurantee 99.99% uptime, and we will handling it for you if your application can tolerate < 1 second delay under some rare abnormal circumstances. 

Final Thoughts
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AWS might be cheap and easy to get started on, but you are locked in with a company which doesn't have any DNA in servers and databases technology.