While OSSM 3 will be significantly closer to community Istio, there will be a few differences in usage to note, largely due to sail operator. 

This page will be the OSSM 3 equivalent of the following, though should be much smaller:

• https://docs.openshift.com/container-platform/4.16/service_mesh/v2x/ossm-vs-community.html

Unlike the page in 2.x, this page:

• Should focus on usage and configuration differences, rather than feature differences.
• Should also NOT contain feature support status, which we will have a separate page for.
• Avoid text that implies that OpenShift Service Mesh is not Istio. Rather, we should describe OSSM as a supported superset of Istio. For example, rather than saying "Red Hat OpenShift Service Mesh differs from Istio...", say "Red Hat OpenShift Service Mesh is a Red Hat supported distribution of Istio that is installed and managed by an operator that is maintained upstream as the sail-operator in istio-ecosystem". 

If the content for this page is small, it could be nested under the Upstream Istio to OSSM migration doc (https://issues.redhat.com/browse/OSSM-6662).