I've used aluminum rivets on some light load applications.

For reference, a 3/16" SS rivet has shear strength of about 950LBS and tensile strength of about 1200 LBS. For a aluminum rivet you're looking at about 350 LBS shear, 500 LBS tensile. I would use that as the the basis for deciding which fastener is better. The corrosion of the base component will be virtually eliminated when using an aluminum rivet (assuming it's an aluminum component).

sm