Is it "much, much better" than the 360 version? It seems like compared to the 360 we have notably worse effects and audio, but higher res and more consistent framerate (but still not fully consistent and we still have frame pacing). To me, it's disappointing that a 360 game is only mildly improved, and in some cases even degraded. This system is supposed to be notably stronger than a 360.
A 720p - 900/1080p and a much more consistent framerate is most definitely "notably stronger" performance than the previous generation. You've also got to remember that it's doing so on a console smaller than the case Dark Souls on the 360 came in.