I've played for about two hours and the game is good (at the very least!). I really don't understand the hate for the batman games, unless you just don't like batman I guess. They're fun, and this one is continuing the tradition. Just like the last two, it has that highly scripted but awesome intro, followed by some fluid tutorials, and then it opens up the map to you.
Also, it runs silky smooth. I have everything maxed and its running fine between 90 and 120 fps. It dipped to 45ish when I was fighting 20 guys in the snow with all the particle effects, but 40 is far from unplayable. I can't speak for amd user though. But the game so far is well optimized.