At less than half the price of equivalent aluminum chairs, these are a deal.  They seem to work fine and are well built and are as comfortable as my old aluminum chairs.  My only disappointment is they feel about 50% heavier than similar aluminum ones, thought not surprising.  Unless you plan on carrying a bunch of them a long way, it's not a big deal.  I have only had them a few days so can't speak to how they will hold up but just out of the box I am very satisfied.