We purchased two of these site-unseen based on the reviews (brother picked them up in Chicago).
The chairs were super easy in assemble, taking about 5 minutes for each. Most of the packaging was recyclable.
I spend about 8-10 hours in one of the chairs daily in my home office. It's quite comfortable and I have yet to get fatigued from sitting in it.
The chairs fit in well in my home office, though the one thing I've noticed is that the flat surface under the seat's bungie cords accumulates dust and "grimblies", which show up pretty easily since the whole chair is black. Keep a duster nearby if it bothers you. This is the only reason I give it 4 rather than 5 stars.