IF you consider the environment and expected product life, chromed bronze will outlast aluminum. If you go out a few times a month, clean and grease them even the aluminum winches will last well over 30 yrs.... On the CAl 9.2 I have Barient 25's chromed bronze that are like new, freshwater, 28yrs young. On the Santana 525, I have Lewmar 16's as primary with aluninum drums. Much smaller jenny than the Cal and no issues with excessive wear. Just maintain they and be sure that the surfaces are clean, no grit in the grease to cause wear.
In racing environments aluminum winches do not seem to last as long and tend to get sloppy. We were just discussing this last week as a matter of fact.
The boat I race on in the summers (Ericson 35-3) came with all aluminum winches in 1987. Every one has since been replaced with Harken chromed bronze.
The boat I race on in the fall series came with all chromed bronze winches in 1987 (Ericson 34). These are the same winches as on the 87 35-3 just chromed bronze. All of the chromed bronze winches still perform perfectly & flawlessly with zero slop.
It is our guess comparing these nearly identical boats with nearly identical race histories, use and winch maintenance that the bearing loads wear or elongate the softer aluminum races much quicker than they would on a bronze winch thus resulting in winch slop.
P.S. Replacing the winches on this 35-3 was about a $4500.00 expenditure that the 34 did not have to spend.
On a 22 footer it may not make a difference but I certainly prefer chromed bronze or stainless like the Andersons.