Less weight the better for me. I noticed that I've chipped some teeth off the front internal diff gears by braking too hard, weight it definately not what I want. The gears usually don't wear, I have 0 wear on the ring gears and the internal gears only stop working when you crack them. It not like a "over time it will wear" thing.

I've seen some hardened ring gears crack too in the RCU forum.