These are great quality chairs for the price. Took about 20-30 mins to put together each chair. Id highly suggest using a powered screw driver (not a drill, if you use a drill you could ruin the chair). A power screw driver with an allen key drill bit will make this go much faster. Using the allen key they give you was taking me forever. By using a powered screw driver it cut down the build time in half. 
When you get the the final step of securing the seat make sure to look at it from the bottom to ensure the gap at the back of the seat is even all the way across. There's no clear center spot for the seat so you have to be sure to adjust it correctly before screwing it on. Also when you screw the seat on be careful not to over tighten. If you do the screws will start to pop through the top of the seat. 
These are great quality and we really like them. Only other thing we did was take off the plastic gliders and replace them with felt as we have hardwood and not tile in our kitchen.