It comes in a short, skinny, 8-ounce glass bottle. Glass is a nice touch, but it's covered with a complete plastic overwrap that obscures the view and makes the bottle feel cheaper than it should.
The energy-drink market is extremely profitable, with many of the 6- to 10-ounce soft drinks selling for $2-3. Coke clearly wants to maintain the same margin: the 8-ounce Coke Blak costs about $2. (The same amount of regular Coke in a can costs 50 cents from most vending machines.)
They're also appealing slightly to calorie-counters, advertising it as "about half of the calories" of regular Coke. Curiously, they've chosen to sweeten it with a lot of high-fructose corn syrup (crappy sugar) and aspartame (NutraSweet), which is usually used as a sugar substitute in "diet" drinks. This won't do it any favors.
My opinion: It tastes exactly as I'd expect Coke to taste if I spilled some coffee into it. The regular Coke flavoring is still prominent at first, but the coffee taste kicked in after a second or two. The lingering aftertaste was the worst of both beverages, combining coffee's bitterness with corn syrup's grimy sweetness.
The rest of the office refused to try it, with comments including "Uh, why?" and "That's scary."
I think the main problem is the poor coffee-to-Coke ratio. There's just not enough coffee taste to appeal to coffee drinkers, but there's enough to repel sugary-soda fans. According to the Consumer Reports review, the canned French version has a stronger coffee taste. (Come on, Coke, you think we can't take it but those crazy French people can? You're un-American!)
The tasters and I unanimously agreed that we would neither want to consume an entire bottle nor pay for one. Since Coke is charging a premium, they're going to have a hard time making Coke Blak succeed.