I have run both, but it seems that regardless of manufacturer, that the top of the line rods are I beams(carrilo, howards, oliver, etc.). when we were doing tensile pulls in college the strength of the pull was more influenced by material type not shape on properly prepped samples. the biggest cause of early failures were from stress risers where someone had nicked or scratched the surface during installation. Bottom line is pick a rod that is suitable for your combination. piston weight & rpm, compression ratio, nitrous or forced induction, are all factors to consider.