My experience with linux power management has been alright, or at least better than my expectations. I have an asus laptop that gets f*-all battery life under windows (either 8 or 10, though it seems to be worse now) but I can usually get at least 90 minutes more out of it under linux. It took some tweaking to get to that point, and I have no macbooks to compare it to, but I think the situation isn't as grim as I see a lot of people say it is.