well,
have you had to dispute charges???
I'd perfer Amex on my side than Citi. --I must have 75-90 charges a month. some need to be disputed. I can't wasted hours with the merchants. That's where Amex helps. That's my "concierge" service.

Citi is known for atrocious customer service. No Verbal disputes
even among its gold account holders & near private bank type accts.
I'm not saying that Citi Chairman is bad. ( I have no way of knowing).

I do know that Citi treats customers who are worth a lot more--to citi in annual profits-- than a $400 annual card fee, poorly is the chairman card so seprate a culture from the organization.