I agree some do look very similar but Ford has so many grille designs for all the trim levels that you can get around the similarities pretty quick.
as a whole, the Ram trucks have so many smooth and round edges it looks like a sedan to me, the Ford balances out the round with the square, GM went to square and hard lines, and Toyota just went straight for hard lines and Transformer look. I think the GM exteriors look the best/most truck like. don't care for the lower level trim grilles on the GM products though.