Personally, I think the Heavy Grade on my SI is nice because it balances it out, since the hilt it self is so heavy. That could just be in my head though. lol.
Same here. Now that the hilts are metal, the heavy grade tends to give a good counterbalance to the blade. I actually prefer them for spinning and whatnot - while I can't maneuver them as quickly, the extra weight balancing the metal hilt gives it nice angular momentum.