They are much more durable than the ones that come with typical shirts. They don't warp easily. I've used one pair for the last two weeks without any issues. I would definitely buy again.
As one reviewer mentioned, there is not much use for the short stays, but at this price, it's hard to complain. The mediums and larges are worth it by themselves. Depending on the style of the spread-collar, both of the larger sizes will be used frequently. All-in-all, a great product.