I'm impartial, being a (Gasp!) John Deere guy, but over the years I have worked both WD's and 9N's, and if you chained the two back to back, the WD would drag the 9N till there was nothing left of it but the gas cap!
They're both good machines depending what you're using them for. WD probably better for heavier work, plowing, heavy bush-hogging, etc., 9N good for mowing, light blade work and such.
Just my opinion.
Now, If you wanna talk about a real tractor.........NO!.....I won't do it on this board.....I won't mention my John Deere A.