[oh8eleven]

Once you get that set home where you don’t have harsh overhead lights you will be able to evaluate things like black levels and ease of long term viewing.
Ease of long term viewing?
Once you get the TV home, you've bought it and then what? You take it back again and again until you find the one you like?
You're buying a TV, not a new pair of socks.

[Varda]

By long term viewing I mean whether the set causes eye fatigue after a couple of hours. I agree with you, once you've bought a set it's yours unless it breaks within warranty period. People take sets back, sometimes for frivolous reasons. I've seen people brag (on-line) that they've taken month old sets back simply because a newer model was announced. Fortunately that web site had plenty of posters chastising people for doing that. Costco had to change their return policy because people abused it.