I hope it's OK to piggyback off of your review...I liked it a bit more than you but I can understand your complaints.
This is a really, really smart redneck film-noir. That's the best way I can think to describe it. I was expecting something different, but that's my own fault for misreading the synopsis(my brain only seemed to process the "Ozark mountain girl hacks through" part).
If you aren't a patient person, or you don't care for more restrained, subtle film making, you probably won't care for this too much. Otherwise, give it a shot. It feels very authentic and realistic(I spent much of my time growing up in the area where it was shot), features great acting, and a perfect score, which compliments the movie while at the same time serving to impart an uneasy feeling upon you. It's powerful too, though like the rest of the movie, it isn't anything you could call over-the-top, and is more of a slow burn that sneaks up on you.
I can only think of a couple flaws other than it being so methodically paced(and that isn't a flaw per se, just a matter of preference), and they aren't even worth mentioning. One of 2010's best.