Just finished it on hard and despite a few flaws I'm incredible impressed with this game. The combat is deep and the game looks great in action, but the bosses are what really put this game over the top. The scale of the Boss fights are simply amazing.
Bayonetta is easily better then any DMC game, but falls just short of NG black for me. Although Bayonetta is great it has a few flaws that stop it from being on NG blacks level. The story... my god the story. Its simply not very good and that's fine NG barely has a story and I don't really find that much of problem in NG. The difference is NG doesn't make you watch a cut scene every 10 minutes. In the beginning the cut scenes are a little back story and lots of Bayonetta flipping around killing angels, which at first was fine but after awhile they felt overdone. Then in the last couple of chapters they get down to telling the story of Bayonetta's past and the reason why she is being hunted, and its not very compelling. With action games game play is what makes or breaks the experience for me, so I'm not to upset with half ass story.
I could probably write a essay on NG Black Vs Bayonetta. I will spare you all and keep it simple, when fighting normal baddies NG > Bayonetta, when it comes to boss fights NG < Bayonetta. I felt like with NG you had to learn how to fight each enemy if you really wanted to be successful and with Bayonetta it all comes down to dodging. With NG some times you had to dodge other times you needed to block or counter while being patient while other enemies required you to be aggressive. With Bayonetta its all dodge, witch time, smash. To give Bayonetta credit this doesn't get old and some how remains satisfying. I just thing NG had some more depth and variety when it came to game play. Boss fights its not even close Bayonetta offers you epic boss fights that are cinematic and fun while NG Black boss fights where not very good. They were hard but you beat most of them the same way dodge/block then swallow drop when you got the chance.
TLDR: Bayonetta is the best action game of this generation and better then DMC but not quite as good as NG Black.