L vs. non-L

Hi,

ok, so I've seen the lab reviews. But in practice, what is really the difference between L and non-L as far as sharpness is concerned? I have peeped the pixels too, but on a 22" wide screen and me a feet or two far from it I don't really see any difference.

Or maybe I did not try out the right things. Would someone have some real-world pictures that would show ?

Thanks !