European McD's are better than the US, or they used to be when they still used animal fat to fry them in, but when you get them fresh and salty in the States?
KFC's potato wedges and Arby's curly fries are great (but I almost always get potato cakes at the latter, dip 'em in horsey sauce and ketchup). Checkers' seasoned fries are less good but still tasty.
Wendy's fries and CFA's waffles are great fresh too.
Burger King, Hardee's, and Sonic? Not if I could choose otherwise, and at Sonic I do. Tater tots every time.
(Oh and there's also Five Guys but that's not really fast food IMO.)