So far, Id give a 4.5! Just put them together today and so far we really like them. The metal legs seem sturdy they are definitely a dark slate grey and not black, which is a bit disappointing but not worth returning because it still works with our space. The cushions are firm and more of a taupe than grey. The cushion sits at 26 off the ground. 
What I do like a lot is the back and seat are all one piece, so when you lean back, there is no give and feels solid. 
Wish I could buy individually as well, so I could have 5 and not have to buy 6 with an extra ) and one of the  chairs has a weird little rust color mark that Ill need to color. 
all in all Id recommend!