the mahle forged are made of a different grade aluminum then the arias and ross. they dont expand as much after warmup so they do not require as tight of a piston/wall cleareance. its the cold starts before the pistons are expanded that really puts the abuse on them. a street driven truck may see 3-5 cold starts a day where a competition motor might only be once or twice a week thats why they dont last as long in street trucks. Guy has almost 80k miles on mahle forged, he told me that he has seen some street motors barely get 12k before they had excessive blow by with other pistons.
I agree, from what I've heard and you can take it with a grain of salt the Mahle forged pistons seem to last pretty long in street trucks.