The one ‘special feature’ I enjoy most out of American Express U.S. lounges is the “wine wall” in San Francisco. I never drink wine onboard in domestic first class, and don’t touch the house wines in US airline lounges. I love nice wines but don’t drink for its own sake.
The great thing about the wine wall is that they serve better wines than you’d expect in a lounge and it’s an opportunity to be introduced to some new bottles you may not have tried before.