CNET did not review the LG LM6200 series, but we did review a very similar product, the LG LM6700 series.
According to LG's Web site, the main differences between the two come down to backlight technology and styling. The LG LM6700 we reviewed has an edge-lit LED backlight equipped with local dimming (more info), which LG calls "LED Plus." The LM6200 does not. While normally this feature has a positive impact on black-level performance, and hence overall picture quality, during our review of the LM6700 we noted poor black levels despite the presence of local dimming. For that reason, we don't expect this difference to have much impact on the comparative picture quality of both of these LGs.
The styling of the two TVs is also different. The LM6200 has a black bezel around the screen, compared with the LM6700's silver. The 6200's bezel is also quite a bit wider than that of the 6700, resulting in a less-compact, modern appearance.
The less-expensive LM6200 series is also available in a much wider array of screen sizes, from 32 to 65 inches, compared with just two sizes (47 and 55 inches) for the LM6700.
Otherwise, the two series have essentially identical feature sets, and we expect their picture quality to be similar as well. For more information, check out the full review of the LG LM6700 series.