What are the pros/cons of an aluminized steel Y-Pipe vs. a stainless steel Y-Pipe?

::crossing fingers that this wasn't in the FAQ somewhere::

 

Well the only one I think that sells an aluminized y-pipe is Warpspeed and they have a 4 year no rust policy on there pipes. The pros of aluminized is that it is lighter and cons is eventually it will rust. Stainless will last forever but is heavier. I say either one is good, as long as it mandrel bent.