This should be moved to either the Plasma sub-forum or the Flat Panel technology sub-forum
1. Plasmas are space heaters, more so than CCFL back-lit LCD panels, Samsung are more so than Panasonic overall, but there are exceptions,
2. It's a LCD LED back-lite TV, not a "LED" TV, which for consumers, there is no such thing,
3. Like CRTs setting of the backlight or in your case the brightness of the panel does affect current consumption, hence the difference in current consumption of these reviews/tests,
4. The advantages of LCD's that are LED edge lit is a thin bezel and panel, cheaper to produce and lower power consumption. The downside is poor brightness uniformity across the screen (flashlighting). Full array LED backlighted LCDs pretty much solve the uniformity issue, but power consumption goes up approaching plasma levels. They are more expensive also.
Samsung had most of that solved with their non CCFL driven DLP's but dropped them in 2009.