Agreed.

One more:

For replication across regions, do you peer VPCs via Transit Gateways or some such, or do it over the public Internet? I ask because a lot of folks complain about exorbitant AWS bandwidth charges for cross-AZ and cross-region communication (esp over the Internet versus over AWS' backbone): At 300k msgs/sec, the bandwidth costs might add up quickly?

Consequently, maintaining a multi-region, multi-AZ VPC peering might have been complicated without Transit Gateway, so I'm curious how the network side of things held up for you.