I'm sensitive to it, maybe not 20ms and above hyper sensitive, but before the TV I have now I had that problem on a large screen Samsung that made gaming impossible. I think the mileage really varies on the argument based on that due to input lag. Some TVs (more in the last 2 years) have been adding in added tech inside to drop that rating down to like a PC LCD but it adds a cost (like $200 2 years ago on a Sony so I skipped it.)

Light guns, 100% agree. There are work arounds people are developing, maybe it'll flourish next year on how to make one or modify an existing zapper as I agree Duck Hunt is fantastic.