as I've got a Samsung 40 " 5500 and unless I put it into game mode the ps4 lags on it, whereas the Sony sets are known for very low input lag out the box..
Game mode is there for that reason, not sure why you would consider it a negative point? Plus once you set it to game mode for your PS4 input then you don't need to change it again.
Sure the Sony also has game mode?