Some are talking about permanent FPS drops (even after Update 5) despite a high-end system.
I do not know what some among high-end understand, but I play everything on Ultra, 1920 * 1080 AA TXAA etc.
I had never been anywhere FPS dips, my system:
Intel i7 4960k (per core to 200MHz overclocked)
EVGA GTX 780 SC ACX
2x 8GB Corsair 1866MHz RAM
2x Samsung EVO 250 (SSD)
Windows 8.1 Pro 64-bit
The single graphical defects that I have encountered in a mission once an ally NPC through the wall, a cat is flown from the sky and there was a (!!) komsiche face distortion. After Update 5 should something be resolved, therefore 1 star deduction for an otherwise completely successful game.
The story convinced me much, but I do not want spoilers now.
As AC fan a must!