In any case, DmC's really hard to call. The reception of the game seems evenly split among people who actually play it, though it does feel like there's a ton of people that outright refuse to play the full game, which tends to mark up the vocal dislike of the game.
For me, it personally ends up being the second best Devil May Cry title ever released, right after 3. I personally got a bit more satisfaction from the higher challenge in DMC3, and thought the Dante in that game was the best version of Dante in the entire series personality-wise. I still like the new Dante overall, though, just not quite as much as 3's Dante.
In terms of overall genre (stylish action), Bayonetta > DMC3 > DmC as top 3 for me. I sadly have little experience with the Ninja Gaiden games. I played Black on my Xbox with a college roommate, but that wasn't entirely my own experience, so it's hard to really evaluate it on the same level.
You should play Sigma 1 and 2, not as hard as the original versions, but frankly, it's a good thing in these games in particular, Master Ninja on the original Ninja Gaiden II is not healthy for anyone, really.
STAY AWAY FROM NINJA GAIDEN 3 --- Aion is just like all other WoW clones, I mean, the Mage in Aion has a Fireball spell and can make Portals. WoW ANYONE??? - Aion Boards