A couple of thoughts:
1. with griddles, a lot of heat gets thrown back at the burners, this leads to erosion of the gas jets, it is worse with gas as well, because gas has water vapor in it that does not get completely burned off. Thus, burners with griddles on the top burn out faster. Stainless is good, cast iron is better.
2. Most commercial griddle are, in fact, mild steel, as carbon steel cooks better than stainless steel, and it seasons, which means, over the long haul, less oil used, less sticking of food, easier cooking and cleanup. Yes, carbon steel rusts, learn to take care of your equipment. Or leave it greasy, either way works.
3. Cast iron and cast alloy work even better, but, have added weight and can reflect even more heat. If you can find a cast iron griddle top, it will last a lifetime, but, so will a 3/8" steel top, if maintained.
4. I used to cook on a carbon steel Teppan (3" thick carbon steel) and it was the greatest thing I have ever cooked on. I could cook cheese on it until crisp and it would slick off clean as a whistle. Stainless will stick and it doesn't sear anywhere near as well.