I think you are confusing an engine maker (amazon) with a car maker (mailchimp)

Amazon SES is simply the thing that sends your content. It doesn’t schedule or decide who it goes to. It doesn’t format the content. It simply sends.

Mailchimp could switch to using ses as a delivery engine. The other services you list are simply ‘Mailchimp’s on SES’

My company - Zonmaster.com – also uses SES. It is not relevant to the service.