Justine has the best backhand on women's tour, and she can't compete with the men, but just looking at the shots she can produce and whatnot, I believe she does have one of the best backhands in tennis.
Safin has a better backhand than Agassi and Hewitt, please! But Nalbandian is up there with him on the best two-handers. Roger doesn't generate as much power in his BH, but the amount of variety it brings to his game is essential to his success. It's one of the best on ATP and an underrated weapon (even if counted as his weakness - well, sometimes it's so off it truly is).
Proud member of Justine's Philistines Society™
"There's a bit of Justine in all of us"