Where initially the clap skate has been met with laughs and scepsis, even by the top skating athletes in 1996, it has become the standard. They are faster and it allows athletes to be more athletic - extending the leg more in a way that the muscles are built for.
Here a link to a classic interview with Rintje Ritsma, while still in denial (in Dutch, but speaks for intself). Link is included mainly for the 20 seconds with Rintje till 8:19.