Discovered a few annoying things with the new Admin Center:
- you can not see the "member of" any longer to check for group memberships
- splitting the groups into sections (e. g. having all group types in one list in the old EAC
- list all mailboxes in one view (e. g. filter for Shared mailboxes rather than having an own tab for each type like in the old EAC)
=> inconsistent experience for mailbox and groups and is exactly the opposite as in old EAC
- adding mailbox delegation is weird (you have to click add permissions first... but you usually tend to immediately use the search field first)
- adding send on behalf permission for shared mailboxes is still missing (it also was missing in the on-prem EAC as well as the old online EAC). You will have to leverage PS for that, while you have that grant send on behalf for regular mailboxes. This was and is a design flaw in my mind. You can add the read and manage permissions from the GUI, but not send on behalf.)