after a while your unsealed headset is gonna start making nasty grinding noises unless you take care of it well
sealed is alot easier to maintain and its smooooooth. unsealed usually spin better, but sealed is definitely the way to go.
of the two that broke, one of them was grinded to fit 125mm wheels, and it broke off.
th other one wasmine, and the race did come off with the fork.
its logical that it was the SCS's fault.