It's really the same debate as carbon vs aluminum arrows IMO. One weighs more and carries more KE through the entire shot, however at the cost of speed and trajectory. The lighter arrow travels faster and flatter, but looses KE faster and therefore inherently doesn't penetrate as well. I believe it boils down to personal preference based upon the type of bow you're shooting, the game you're hunting, and how far your effective range is.

I shot aluminum arrows with 125 grain tips for years and years and years and never had a problem with them. However, I wanted to increase my accuracy and speed at a little bit further distances (in my case, out to 30-35 yards) so last year I made the switch to 100 grain heads and a faster bow - but kept my aluminum arrows. I punched 2 arrows clean through 2 deer and had them stick in the ground afterwards. Being happy with those results, I have now switched to a lighter a/c/c for this season in hopes of once again increasing my accuracy down range any hopefully not sacrificing too much KE and penetration. The choice is ultimately up to you as to what best suits your shooting ability and gives you the results you're looking for.