Unsprung weight would be the main issue.... I use either DOM or moly for mine. I like the strength...

In the overall performance of the suspension system, 1 pound of unsprung weight (control arms are unsprung weight) effects the performance of the suspension about the same as 10 pounds of sprung weight.... Contorl arms and spindles have to be strong, but they should also be light as possible to improve the handling....