We still accept Amex, but I keep questioning why. As a vendor, they're a PIA to deal with, and I have yet to have a customer who has an Amex but doesn't also have a Visa or MC....
They offer monstrous amount of points for the users, which is why they charge the merchant so much.
I agree though, PITA.
EDIT: They are also VERY lenient compared to Visa/MC when it comes to giving credit to businesses. Good friend of mine opened a mechanical shop a few years back, Visa would not give him anything because he didn't want to use his personal credit so he could build the businesses' credit... Amex gave him 100k.