For me, some episodes earlier in the season felt a bit stale and monotonous. While the latter episodes were far more entertaining, the season finale delivered everything that a season finale should - blowing all previous episodes clean out of the water.
There were a few minor niggles but since it only accounted for a second or two of screentime at a time, they were nowhere near enough to detract from the enjoyment. One minor niggle was that personally I feel Duke was kind of cheated but the Colorado comment seemed to make up for it.
It had comedy, reveals, reunions, action scenes, deaths, heartbreak, twists and a huge cliffhanger that'll leave you counting the days till next season. I can only hope the rest of my favourite shows deliver a finale of the same caliber.