I've fallen, hard, for Justified on F/X. I didn't want to. As far as US Marshal series go, my heart is still held captive by Jeff Fahey in The Marshal and Carla Gugino in Karen Sisco . They set the bar and were both cancelled too soon.
But Timothy Olyphant as Raylan Givens does a great job, and I thought the show "felt" familiar--then I saw the credits; it's based on an Elmore Leonard short story and he's listed as one of the executive producers. So it has that kind of off-kilter weird story vibe that I loved so much about Karen Sisco, as well as that smart-but-slow-talking hero I adored in The Marshal.
The supporting cast, especially Nick Searcy, Givens' long-suffering new boss, are uniformly great. The show isn't very dark, though that might change when we see Givens' career-criminal dad. Or it might not.
But it gets my recommendation, for what that's worth.