I have the business version of the card, and the $500 annual fee is justifiable to me (even though I will most likely get it waived this year and next) on account of the $200 travel baggage credit, and the TSA pre-screen fee waiver. The no-limit on charges also helps, as I frequently run $100,000+ through the card on a monthly basis.
Their Centurion Lounge in SFO is also pretty boss. The wine bar is amazing, as is the food, shower, and relaxation area.
Back on topic, I haven't yet used the travel credit for anything other than baggage fees, though, so I'm afraid I'm not going to be of much use. :(