I'll keep this short and sweet: if you're in the market for a high-end TV, the LG OLEDB7A should be the first on your list.
Why, you ask?
Now, I haven't tested the B7A directly, but I did perform hands-on comparison reviews of the LG C7, the LG E7 and the Sony A1E OLED TV. Based on those tests, and LG's claim that all of its 2017 OLED TVs have identical picture quality, I feel just as comfortable recommending the B7A as I do the C7 or the others.
The picture on all 2017 OLED TV's I've tested is simply the best I've ever seen, better than any other TV I've ever reviewed. OLED stands for Organic Light-Emitting Diode, and it's a different display technology than the LCD used on most TVs. Unlike LCD (including QLED), it exhibits perfect black levels for unrivaled contrast and "pop," and stays true from off-angle.
Only LG makes OLED TVs in large screen sizes, although other brands like Sony, Philips and Bang & Olufsen buy panels from LG Display and sell the TVs under their own brands. LG introduced the B7A in late August 2017, months after its other 2017 OLED models were available, and it just started appearing online and in stores.
So, about those differences. The C7's stand is pretty cool, but then again so is the B7A's -- it looks a lot like the stand on the 2016 B6, with a chunk of transparent plastic above a metallic base.
The audio differences are also minor. LG says: "Although total audio power is 40W for each, the C7 has 2 woofers (2.2 channel) while the B7A does not (4.0 channel)." In other words, the C7 might have slightly better bass. Big woop.
LG says that although the B7A is "not an Atmos TV, it would still be able to pass the signal through to an AV receiver." In other words the TV's speakers can't decode Dolby Atmos themselves, but the TV can pass along the Atmos audio from its built-in Netflix or other Atmos-capable apps to an Atmos-capable AV receiver or sound bar, for example. Since most people who care about Atmos are using a receiver or sound bar, rather than the much lower-quality speakers on the TV itself, the B7A's Atmos capability is plenty. Thanks to Bill for the tip.
Otherwise the C7 and the B7A are the same, and since I expect the B7A to continue to be just a bit cheaper than the C7, it's now the best value in a OLED TV. Yes it's still really expensive, but don't be surprised if both TVs experience price drops in the lead-up to the holiday buying season. How low they'll go is anybody's guess.
(By the way, LG also makes a "B7" OLED TV, without the "A," but it's sold exclusively at club stores like Costco and BJ's. It has the same stand as the B7A and the same audio capabilities as the C7.)
Updated February 8 2018 with additional details on the B7A's Dolby Atmos capabilities.