The 55-inch Samsung is the top LED TV in the Samsung 7 series. Compared to the UN55B7000 the UN55B7100 features 3,000,000:1 Mega Contrast. Besides that I could not find a difference besides the difference in the frame color.
Of course the Samsung UN55B7100 (MSRP $3,599.99) is not as advanced as the current ultimate LED HDTV from Samsung. The Samsung UN55B8500 (MSRP $4,499.99) has a 7,000,000:1 Mega Contrast and 240Hz instead of 120Hz.
To see if the Samsung UN55B7100 is still a great choice for an LED TV consult this review just posted by HardwareCanucks.

Quote from the review: "HDTV technology is changing at an incredibly fast speed and companies are forced to come up with unique and interesting ways to stay in the consumer's mindset in such a fluid environment. With their new LED-based LCD TVs, Samsung is thrown down the gauntlet to the competition by releasing an incredibly thin and energy efficient product that also costs a small fortune. Can this new technology take LCDs to the next level? Let's find out."
Read the full Samsung UN55B7100 LED HDTV review on HardwareCanucks.