The one that always jumps to mind is, on "Small business Saturday", if you register beforehand:

- visit a small business on their qualifying list, which is quite long

- Spend $10 or more on your AMEX

- Get a $10 statement credit

I don't know how "notable" that one is, but I always liked it and not everyone knows about it

Generally AMEX is known for better customer service, but YMMV. AMEX is often seen as a good choice for people looking to build credit because they're often willing to give out a 3x credit limit increase (without a hard credit pull) first 90 days after getting a card, and then every 6 months after that (up to a point and assuming you're using the account and in good standing).

Purchase Protection.

This saved me recently. Broke my new Nexus 5's screen in a matter of a week. Sent to LG for repair and they repaired it for 150$.

I filed a purchase protection claim for this 150$ with AmEx and they refunded me the cost in a week. Just emailed them the claim form and receipts. Can't recommend this enough.