Originally posted by systemA
1/2 stop really isn't that much, but sometimes that faster shutter can be the different between catching something in motion and getting a blurry subject. If you really need 1/250, get a HSS capable Pentax flash.
As I understand it, the flash duration is much, MUCH less than the actual shutter speed. If it wasn't, the sync speed would never be an issue when shooting with flash, as the light would be constant over the whole exposure.
If you're using the flash as your primary light for the exposure, you should be able to freeze really fast motion easily. If the flash is NOT your primary light source, you run into trouble.