Gotta cheer for my own team.
Weight training has a tremendous amount to offer, it often includes stretching aswell. I agree with fawny, depends on your nature but if i had to logically compare the two (assuming exercise refers to weight bearing exercises) Exercise would win hands down.
Yoga builds discipline and can be hard and can improve posture but it won't make you as strong or resilient as an athlete. Spirituality is a very individual thing too, personally i don't like the word or it's associations with certain activities or groups and not with others. I think i would describe it as strength of character or personal development, any activity can potentially be spiritual.
TO conclude, weight bearing exercises can do everything yoga can do and more due to the increased external resistance.