Stainless vs Enameled Porcelain Grates? I need to replace the grill grates on my Weber Genesis grill, and I see that I can get either enameled porcelain (like I already have) or upgrade to stainless steel. 

A few concerns spring to mind when considering the upgrade:


Are there any differences between the two other than appearance? 
Does one hold heat better than the other? 
What differences are there to the grates' maintenance/upkeep/cleaning/appearance?
Prefer the larger, heavier grill.  It's about thermal capacity and grill marks.  You want the grill itself to be hot so that when the meat touches it, it immediately sears the meat on contact.  The bigger the thermal mass, the better this works.

Regardless of what you get, you're going to need to replace the grates every few years, so bear that cost factor in mind.