Since I am used by now to the many differences among these 3 decks and others I also have, I was surprised at how similar all Hermits are.
Marchetti's is just a more artistic version of RW's and he is facing the other way, but he conveys the same meaning to me, so this is the easiest to read for me.
Llewellyn's portrays the famous Merlin, so to the Hermit's usual wiseness and solitude he adds power and magic and the ability to lead others. Still, the image is very similar to RW's, except for the snake, maybe.
And finally the Universal Hermit looks younger, straighter and more like he is guarding a castle or tower than the light of wisdom.