Just as a point of clarity, LCD and LED are not competing technologies. The LCD is the actual display element and the LED is the lighting behind it. LED TV's also use LCD displays. If a TV is not called "LED", then it's safe to assume it uses compact fluorescent bulbs behind the screen.
The dot or pixel "pitch" is the distance between pixels of the same color. If two displays have the same resolution capability, then the smaller one will have the pixels physically closer to each other.
There could also be differences of signal processing. Maybe one is a better tier model then the other, newer one could have more modern processing. It could also be the "crispness" of the brighter and more even LED lighting then your fluorescent lighting (which fades over time).