To be VERY blunt... edge lit LED backlight systems suck. I personally would never own one unless it was a smaller size screen... like maybe less than 40" diagonal. And then, it would only be for casual use in a bedroom or study or sitting room, not for any critical viewing.
If you purchased the set from a retailer with a return policy and you find yourself not happy with the image, it would certainly be your right to return the TV if you were willing to pay more for a TV with an LED array behind the screen which will have much more uniform illumination. There are two kinds of 'behind-the-screen' LED arrays... white LEDs or 3-color, red, green, blue LEDs. If you are going to have the TV calibrated, the RGB backlighting seems to be more "calibratable" than the white LED TVs. And if you are interested in calibration, you'd be better off with a TV that has good calibration controls that work. The best calibration controls available right now are on Samsung's better models where you will find 10-point grayscale/gamma controls that most TVs do not have. You won't find good calibration controls on Sharp TVs and Toshiba controls don't work very well. Panasonic and Sony have limited calibration controls. AVS is great for researching this sort of information BEFORE you spend money on a TV.