I was considering moving up from the Delta AMEX Gold card to a Platinum but the only real difference was the companion ticket.

When I called them (in December) they said it could only be used when flying with a fare paying customer who has spent at least $345 (give or take a few $) for their ticket.

Also you don't get the companion ticket until after you're renewal. Basically I would be paying $100 (2 years of at $50 for the step up) just to get my companion ticket. I might still do it.

I've compared them on this web site:
http://www.americanexpress.com/deltaoffers

Does anyone know of any other real benefits of going from Gold to Platinum for a leisure traveller?