From what I have read I gather that the aluminum case o/d is weak and the cast iron one is much better strength wise but not as tough as a standard 4 speed
yes, but even still the aluminum is still a lot stronger than what is commonly written.
Even I have had the aluminum ones come apart on me but if you drive it normal there wont be a problem.
Best bet if you want anything to last is try not being an ape.......when I had them come apart on me its because I was driving like a she-ape and you cant really blame a part failure that was abused beyond normal.