Unflinching courage doesn't really fit for it's cost. Believe me I considered it, but it leaves much to be desired. I'd rather make it naya and play boros charm and madcap skills!
They totally are, though! I've only played it in two FNM's. The first, was a slightly different build than the one shown here, and I went 4-1. The second was this exact build and went 5-0