Put simply, and without a doubt: it's remarkable.
I don't watch much true crime, and yet I'm not sure that label really fits here. "Burden" is deeply humane, entirely un-sensational, and far more artful than anything I know of in that genre.
It's a special and gripping work, with a haunting though subtly conveyed reminder of the pervasiveness and elusive justice around partner violence.
And in terms of filmmaking craft, it's an impressive display of both endurance (the project stretches over nearly 8 years) and skill (cinematography is deft and compelling throughout).
It's worth your time. And you'll be thinking about it.