Hasta La Motion!

What’s the difference if I render a video @ 1920 x 1080 aspect square, or…1440 X 1080 aspect 1.333 ???

When I observe them up close, they look the same.
If there are 1,920 pixels by 1,080 pixels in a given area. And those pixels are square in shape, is that better than 1,440 pixels by 1,080 pixels in a given area that are enlongated or stretched?

My instinct is to say, the more pixels the better, however, if you think about pictures, if you took a 720 x 480 picture, then rendered it at 1920 x 1080, do you now have a HD image?…No you don’t and the image would be pixelated to boot.

So my question is:
If the native video format of the HDCanon is 1440 x 1080 1.333, what gives the BEST resolution, 1920 x 1080 square, or 1440 x 1080 1.33 when rendering it out of nuke, After effects, etc..???

Thanks,
Lou