They recently rebranded it to the super-catchy "AWS IAM Identity Center (successor to AWS SSO)". Gotta love Seattle-based tech marketing people, presumably trained at Microsoft. :)

I guess it will soon be the default user management system, and 'proper' IAM will be the low-level one. I see this as a reaction towards GCP's IMHO superior UX/system design in this aspect. I don't think they can entirely catch up because of early and bad architectural decisions regarding projects/accounts.

Also a fan, so far.