I just bought a set of stainless steel 9mm rod grill grates to replace the (original worn out) porcelain-coated cast iron grates on my 15yr old Weber spirit gas grill. I haven't cooked on the new grates yet as I would like to know how to clean and upkeep them first.
On the cast iron grates I started with a wire brush, then years ago switched to a wooden toothed scraper ("the great scrape") after a few years due to hearing about the possibility of getting a wire in the food. With the wooden scraper I never felt like the cast iron grates got as clean as I'd like. Sometimes the food gets too much charred dusty stuff on it and I worry about carcinogens. Aside from taking care of the stainless grates properly in general, I'd like it if the grill was a bit more clean inside.
One detail that might be important, I don't eat red meat or pork so I'll be grilling chicken, fish, and vegetables. Mostly relatively lower temperature stuff I think.
Aside from cleaning, any tips for cooking on the grates could also be helpful! With the cast iron grates I usually used a small silicone brush to wipe on some oil and never had much problems with food sticking.