I noticed the frame drops last night right away. It's a bit distracting, same as the shimmering on distant detail and it all looks a bit washed out, there's no black. But eh, pick up an axe, chop down any tree you want, can't do that in HZD!
What disappointed me more is how quiet the game is. Maybe it's just the start yet I'm missing background music, environmental sounds are very minimal and 'talking' to npc's is restricted to the occasional 'hmm' sound.