It's 4.1% vol and I'm not entirely sure what to make of it, to be honest.
It's got a good, solid black colour and has very little appreciable head. Even though they have copied Guinness by adding a widget to the can. Never had a flat can of Guinness with or without the widget, but I digress. (Maybe how I poured it?)
There are harsh and bitter coffee tastes to it, which leaves a not particularly pleasant aftertaste on the palate.
I think there are also chocolaty hints, too, plus perhaps something else. Liquorish, maybe? I don't know, but it doesn't work well with the overall flavour, sadly.
In their promotional material they seem to be knocking Guinness for being old and boosting Black Heart for being new.
But it's all in the taste. If it tastes good, the age of the recipe doesn't matter.
However, what's better than Black Heart and also, perhaps, Guinness? Brew Dog Layer Cake Stout, which is a perfect pint of great, stout-hearted goodness!