I'm not American but I do use Amex and buy almost everything on it, including through PayPal where online sellers don't take the cards directly. Processing costs are high and retailers tend to hate it. But it's funded a shed load of free BA flights over the years as you can swap Membership Rewards points for Executive Club / Iberia Avios, so it still gets my thumbs up every time !
"buy almost everything on it ..." where ? in ibiza ?? definitely NOT.
actually if you go to ibiza and you just come with an amex-card it will be a desaster.
(almost) everbody hates it - only very very few places accept it because theese greedy bastards have by far the highest costs.
only the big hotelcompanies and carrentals accept it ... many beachclubs, shops, restaurants NOT.
their standard answer when you ask is, yes ec-card and all credit-cards -
besides amex.
i had to learn this the hard way - when most of my other stuff was stolen !
i still have mine, but more or less just for "nostalgic" reasons.
99% i use mastercard/visa.
already back in the day in usa - f.e. in the tiniest t-shirt-parlours in venice beach-
they accepted mastercard and rejected americanexpress.
so from private standpoint relying on americanexpress in ibiza is an absolute no-go !
but nevertheless a company like ibiza-spotlight should give the customer the possibility
to choose between all big creditcardcompanies - including amex.