what is the difference between linux enterprise AS & ES?

Answer 1

AS supports more hardware - has no CPU limits ES has limit of 2. AS has no memory limit, ES limit is 16 GB. AS supports "IBM POWER processors" ES does not.

The best place to find this is on Red Hats Site.
https://www.redhat.com/rhel/compare/
For most of the world ES is fine. Heavy Requirements might dictate AS.

Hope that Helps
Merry Christmas and God Bless