I hated taking AMEX when I had a merchant account (needed to because of the types of customer I had) and when I had an AMEX I had various problems, including in the USA. In fact, when I had problems in a store in Las Vegas, I was told that most Americans hate American Express - and suggested MasterCard to me.
I've now got my Visa debit card and a credit card I rarely use, plus I also got a Virgin card that is Mastercard - but, again, don't use (only got it for a balance transfer).
Nevertheless, if you can get a card that has more benefits than it costs and use it only for a specific purpose (e.g. paying for petrol and other large costs, then paying it off immediately) then I suppose it's fine to have - but not for day to day use.