We're pleased with this chair so far. However, ten days after successfully assembling our chair, we found a sheered off preinstalled screw on the floor beneath the chair. (It did not have  the same 'Allen-wrench head' fit of the 3 types in the assembly kit)  We'll ask Wayfair's help to solve the mystery 
and report how they handle the situation back on this platform adjusting our stars as needed. We don't expect a lingering problem that will change our good opinion of Wayfair, however.