Actually anti-refective coating of surfaces on LCD simply scatter the light by having a "less flat/even" midcro surface structure (think polished vs sandblasted).
So instead of reflecting beams of light of a given input angle at just a certain output angle (your eyes...) it will split em up to multiple ones etc.
Side effect #1 is that this surface will also scatter the light emitted from the LCD panel resulting in some amount of funky subpixel interpolation.
Side effect #2 is that in a bright environment all the scattered light reflected from the screen results in less low (worse) black levels.
Side effect #3 is that this surface will be overall less transparent (more "milky") resulting in a lower contrast.
Also some people seem to be capable to spot the micro structure itself and find it irritating...
Anyway, I prefer coated LCDs as I find reflections more irritating than the mentioned side effects