I reckon contrast is more important than peak brightness. The eye is good at adjusting to brightness, and 1000 nits just seems overkill. You might need that much if the TV is surrounded by a white wall directly lit by the sun, but in normal indoor lighting conditions it just seems excessive.
It might be noticeable, but as someone who has trouble dialling down the brightness far enough to make them comfortable to look at, I'm not sure if I'd want it to be that bright. That might just be a personal preference though, obviously.
