I have broken two aluminum roller rockers, probably factory defect.

From what I understand is the steel ones are stronger for those huge lift  roller cams. I know a guy with a 0.990 lift in his Cuda and he will run nothing but Crower steel rollers

For instance in an application like mine (roundy rounds), I read and have been told that chromoly steel (comp cams) rocker arms are guarranteed for life , 5% lighter at the valve , rebuildable , blah blah blah..... Is there any benefit from aluminum to the steel ones or is it all personal preference .

-beerjet-

A few extra HP's from not moving the weight around...
Less stress on other components form throwing that weight around...
less Cam wear, less Load... at at a cost of Strength ...  but Aluminium  has its limit's

If you want safe, Steel is Great (minus factory defects if any like all things)
I always thought Titanium would be a great metal for motors 

Rebel

Aluminum work great, lighter which helps with the mass and reliability of the valvetrain at higher RPMS. Most of them like Harland sharpes have needle bearings which free horsepower. At about 600 lbs spring pressure though, the aluminum will fail.

A guy running 900 lift cannot use an aluminum rocker due to the valve spring pressure required. A 600 lb spring will work with a solid roller until about 700 lift at 7500 rpm.