For it's first winter on the car my aluminum magnaflow resonator has done alright (No surface rust yet). I even let the car go without a wash a lot longer than I did the previous winter. Any surface rust on my stainless tips came off easily with rubbing compound.
Stainless is better, lasts longer. It will outlive your car. I'd say it's good for people who will truly garage their cars each winter. Personal value when it comes to a ten year old platform imo.
