Sherman Williams v. Benjamin Moore
Having recently painted the Ben moore and doing every room in my house in Duration, I will give you my opinion, but again, like slick said, it is coke vs pepsi!
BM, goes on great. Covers extremely well!! Silky smooth and strong. Colors are insane!
SW Duration - Goes on like silk! 2nd coat feels like a 4th!! No joke! My Duration room washes noticeably better than my Ben Moore room. But the BM still washes great! My BM colors are a smidgen nicer than my SW.
If I painted another room tomorrow, I'd go for Duration. If my friend painted his room with BM, I wouldn't be able to make argument against it. Good luck.