Drop-in bedliners:
Less expensive but, they rattle, you lose some bed room, will eventually rub the paint off of your truck, not repairable, could fly out of the bed, very slippery, good impact protection.
LINE-X with LINE-X Xtra (optional product):
More expensive but, resists fading and will hold its gloss, does not rattle, can't fly out of the bed, is repairable and comes with a limited lifetime warranty, is much better looking that a plastic drop-in, is available in black or color-matching, not as slippery as a plastic liner, you don't lose room in the bed.
The Nissan bedliner is by PPG (a paint company) and is applied as thin as paper and doesn't even compare to a LINE-X bedliner.
Here's some LINE-X pics, you won't find any drop-ins that look this good!