The hypers are lighter, and usually have a teflon alloy skirt to help rubbing the cylinder wall. They can rev faster and higher cause of the weight savings, and they dont expand as much when they warm up. They are just fine for NA engines.
Forged pistons are stroger, but a bit heavier and hold up better to NOS and forced induction. So neither is really better than the other unless you plan on pushing the pinging limits then go with forged cause they can take more abuse.