Too slow
I kept getting bored and looking for things to entertain myself with while waiting for the next thing to happen. Tarantino was seriously self-indulgent with the unnecessary lingering on the scenery and the mundane tasks. A faster pace would have improved the movie immensely.
And no, I don't have ADD; I'm a patient viewer, and I don't mind three hour movies - when there's enough going on to justify that runtime. This, on the other hand, is a standard length movie stretched out to three hours for no good reason. The glacial pacing is the critical flaw, here.
Tarantino: "Hey, isn't it cool how they had to make rope leads to the outhouse and the barn so as not to get lost in the blizzard? Here, let me show you how they make those for twenty minutes. Yes, they're totally supposed to stick all the rope-lead-sticks in the ground right here in the foreground and make longer and longer trips back to fetch just one at a time."