Great finale. Would have liked to see the rabbi and some more supernatural elements return (maybe), otherwise I pretty much loved it.
I can see it being a disappointing finale for people who had certain expectations, like a Molly/Malvo faceoff, but I actually vastly prefer the Gus/Malvo faceoff. I thought Gus was so dumb for going into that cabin, and clearly my assumptions about him meant nothing. It was absolutely perfect for Malvo to be hobbled by Lester, who he underestimated, and then ended by Gus, who he vastly underestimated. His own arrogance was his downfall. Look at the shame in his face before Gus fills him with bullets. It was the most comprehensively humiliating defeat for him.
Malvo also underestimated Molly, to the point of ignoring her existence, and of course she made everything possible. I certainly didn't need her to pull the trigger.
If anyone is unhappy with the finale, I'd like to hear why, because I do have some more thoughts about it.