Had read before it's not good to use petroleum based products on some plastic surfaces, like plastic chrome, though I've done it a couple of times on my bike because it looks great at the moment. It's supposed to degrade the chrome finish over time, so they say.
I know Rain-X does wonders for scratches and light pitting on windshields, if only they could make it last longer than a few days.
The Meguiar's is good stuff, my friend carries his in the tail trunk, so I haven't had to buy any.
He's got the rag and bottle out at almost every stop. Tried to tell him he needs to wash the dirt off first, but... I make him stay away from my bike with the sandy rag.
Been using Sprayway foam, ammonia-free, glass cleaner on my visors and helmets for a few years, works well and loosens the bugs pretty quick. And for glass, it doesn't streak like Windex does. Walmart has it.