I just completed Rogue 30 minutes ago! Rogue was a great game. It uses the same exact engine as Black Flag, but exceeds Black Flag in terms of story. I also own Unity, and all I can say so far is that it is such an unoptimized game (AMD card), very laggy on even high-end hardware. I'm not too far into the game yet, but Rogue is certainly well-optimized and performs very well (though I did have one issue where I had to lower environment setting to make the game stop crashing).
I'm installing Syndicate as we speak. Oh, and also, Rogue can be easy, Unity is harder and Syndicate I hear is even harder.
Also, unity basically stress tests your GPU and will make it hot. I did notice that turning Vsync off near triples performance in Unity.