@zeusky, not sure where the hard ones come from but I can find out.
The benefit of the hard ones is it more like a cricket ball that the soft ones.
A: it really hurts when you get hit.
B: it has a more realistic bounce like a cricket ball, not bouncy like a tennis ball.
C: it give a real good impact on the bat, just like a real cricket ball.
I've found the softer ones are easier on bats but are less realistic in bounce and feel.
Negative about the hard ones is they are like cheap cricket balls. Really hard and break bats.
But if u want the closest thing to a real cricket ball then it's the harder ones you want to go with.