Both types of arrows have there advantages and disadvantages. Aluminums are usually straighter and more forgiving in accuracy. There are less durable. Carbons, are not as straight but were talking thousandths of an inch, they are faster, and they are much stronger. Speed is not a primary concern. Yes, a little speed can help, but it doesnt matter how fast the arrow goes past the deer. As for the penetration, the diameter of carbons is smaller which helps it but the aluminums, since in most cases are heavier, pack more punch down range. Carbons also cover a wider variety of spine for your bow. You dont have to buy a new arrow for every couple of pounds gained like you do with carbons. I currently shoot carbons. I really like them. However, i shot aluminums for a long time, and still like them. Im one of those guys that is always changin stuff just to have somethin to tinker with. The last choice is yours, but hopefully this small bit of info will help.