The big takeaway I’ve seen is that the SkyTeam Elite Plus level gives one “SkyPriority” whereas the basic Elite level does not.

For domestic flights, this means priority checkin, baggage handling, boarding, and security (at select airports).

For international flights, you get all of the above plus lounge access. And I’ve noticed when flying partners you get more recognition, access to better lines/boarding, and generally better service. Basically you aren’t in the same lines as the masses.

You need to achieve Gold Medallion or higher with DL to get the Elite Plus level.