I dunno how I feel about Bayonetta's grading system. On one hand, it doesn't knock you as much for style as DMC games usually do, but they kinda kill it by making the alfheim portals mandatory for the higher ranked statues (And unlockable character in the end).
And given how anal and by chance some of those could be, you could drain all your time trying to get past those. And I'm saying this as someone who has managed to S rank every mission in DMC4 across the board.
. . . Though I realize that isn't much to brag, more like "call us when you do the same for DMC3 or Ninja Gaiden".