They are of decent construction, I have several sets still in good condition after a couple of years of moderate use. If you look after them they will serve you well, but I don't think they will stand up to much abuse.
Similarly, the included carry bag feels like it would easily burst if you are not careful. It's a tight fit and there's a bit of a knack to get both poles in.
Overall, this speaker stand set has exceeded my expectations for the price and has been excellent value. You just need to look after them. Would recommend these for anyone using lightweight speakers.