I do have to say - I usually dont compare games a lot in reviews but Horizon almost FORCES you to compare it to other games because it wears its inspirations on its sleeve.
There were so many times I was thinking "this is like the best bits in The Witcher, the best bits in Enslaved, or the best bits in Red Dead Redemption, or in Far Cry 3", etcetera. The combination of all those different influences creates a new, unique product and it just works.
So I really understand the comparisons, I am making them myself. The beauty of it is that when compared to those classics, Horizon shines just as brightly.