It's way better than on consoles, and it actually arrived on PC (which was a really slim chance) that's what matters
Yes the level design is just pure genious, it's also extremely rewarding for an open world game, because "beating" an area, or just getting through it, can be a very demanding task (compare to Oblivion or Skyrim where you can explore the whole world as a level 1 and without too much trouble).
It does have some forest areas, but they're not that large.. Still haven't explored the whole game though (40h into it)..