Well in either case, one nice thing is that this is a major that comes with a lot of variety in between decks. Many artists take quite a few artistic liberties or come up with some really interesting and thought-provoking spins on the concept. That said...
There's a lot I really like about how the Shadowscapes tarot does this card. I love the concept of the Hierophant as a tree - steady and grounded, hard and strong and unmoving, unyielding, old. It's made better by the fact that it does have a kind of severe face/expression, and that wizard's staff, amusingly enough. It kind of brings together a lot of the underlying concepts of this card while completely removing the religious connotations/imagery present on the RWS and its closer clones. Which is useful to be because a lot of the time, religion is quite not what this card is really about in religions, and yet that has so many connotations for me personally it makes it a bit hard to separate from while reading. And of course, I love the nuanced details here, the colors used as well. Creator of this deck is an amazing artist and it really shows in this and other cards.
Runner Up:Well, makes sense to pick a traditional take on the card that's all about tradition among other things, right? I may not like the RWS version of it very much, but the Thoth? Yes, I do quite approve of Crowley's approach. I like the ancient Babylonian look to this hierophant. Like all the cards in the Thoth deck, this one is chock full of esoteric symbolism. I'd be doing it a disservice trying to detail what I only half-understand but I do love that it's there, adding meaning to the card and waiting for me to study it/know it better when I get the chance. Mostly though I love this aesthetically - the orange and dark tones, the lighting effects, that window in the back, the masks - it all really adds to this image of forbidding, powerful, sacred, removed from the world, construct. Very much brings to mind a whole bunch of ideas and concepts associated as soon as I look at it, which is helpful in readings and yeah. Thoth. Does it right.