I recently signed up for the Amex Platinum card. With many benefits, the most eye catching ones being free airport lounge access and $200 worth of incidentals reimbursed on one airline in a calendar year. The program has received some flack recently because US Air/American lounges recently backed out and you can no longer bring guests for free ($27/head now). As someone who usually travels solo and generally flies with Delta, this didn't sting too much. With 40,000 bonus points with $3,000 spend in the first three months, the card almost pays for its first year so I decided to give it a whirl.
The card gives you a free membership with Priority Pass, this means access to over 600 lounges nationwide. However, to access these lounges you need to get a membership card in the mail which is probably about 2 weeks from when you enroll. There is some fine print and you can actually access Delta, Centurion, and Airspace Lounges with only your Platinum card.
So, excited to take my new shiny platinum card for its maiden benefit voyage. I stroll into the sole Delta lounge at O'Hare. I present my ID, card, and boarding pass to the agent and get turned away! Somewhere in the fine fine fine fine print, you must be traveling with Delta (I was on United) to use this benefit, otherwise you can use your Priority Pass card. I called Amex to confirm this and sure enough it is in the fine print *somewhere*. I fly to LAX through Detroit tomorrow on Delta. Hopefully this round will post better results.