Aluminum vs. steel roller rockers?

I'm looking at 2 sets of roller rockers for about the same price, One are the Comp aluminums, the others are the stainless steels from KMJ, This is for a street engine, what would you use? There chevy stud style rockers. These.

http://www.ebay.com/itm/Comp-Cams-H...Parts_Accessories&vxp=mtr&hash=item4843d77127

http://www.ebay.com/itm/SBC-Chevy-S...Parts_Accessories&vxp=mtr&hash=item5adfb7cc25