One slight difference on the Concierge side: I have both the Ritz card and the Palladium card. The concierge said that while the concierge could be the same group of people, but the Palladium members would be flagged as a "Premium" member and receive different treatment as Ritz card members.

Also, both cards come with the Lounge Club card for both primary and AUs, but Ritz card do not charge AU for a fee up to 3 AUs, but there is a $99 fee for Palladium AU.