First off all, just to make it clear, there is no such thing as a LED TV on the market today, it is a scam, what you get when you buy a LED TV is a LCD TV with LED backlight.

Better than an old LCD but still not as good as a Plasma TV.

3D is still overrated and there is not much material to watch, I would not have bought a TV becouse 3D but most new TVs has it, the rule is to buy a TV due to the picture in your living room after calibration, do not trust the picture at the shops.