I have GrillGrates on 2/3 of my Weber gas grill and I use them all the time. I hardly every used the cast iron grates any more. GrillGrates are modular and flat on one side with elevated grates on the other, so you could grill bacon and pancakes on the same grill at the same time
, or grill salmon on a flat module and grill asparagus, complete with sear marks, on the other.
I've never put mine in a dishwasher, I just scrape them clean.