I used to have to replace my flights every week (I once wrecked a set in a single session!), but these ones last far longer and retain a perfect “+” shape even after Robin Hood shots where a dart lands right on top of the previous one thrown.
The durability is great, but there are two other important advantages I've noted ; stem grip springs are no longer necessary, as the fit is so good there is no slack. Secondly, the tight fit means that I very rarely damage a stem with an incoming dart. Usually when that happens the dart bounces back and doesn't score, so they may even be improving the total number of scoring darts?
It's definitely worth adding a set to your next order to see for yourself. They're widely available, with Pure Darts being a good buying option.