The answer is simple. It depends on your personal preference and the distance that you do. It is clear that every triathlete benefits from triathlon laces, because you can quickly change in the transition zone from biking to running. But which triathlon laces are the best? When do you use elastic laces and when do you use quick release laces?
In general, triathletes and duathletes experience that elastic laces are a bit faster then the fast quick release laces. The Xtenex Laces are examples of elastic triathlon laces and you only need to stick your foot in your shoe to put them on. That is beneficial for shorter distances when every second counts. The stability can be less, because they are a little bit looser around the foot.
Greeper Laces als quick release triathlon laces who are steady and stay tight around your foot while running. This is essential for longer distances like the Ironman. This lacing system may take a few seconds longer, but is very reliable and gives good support along the whole distance.