With the irritating Xbox 360 d-pad, Ms. Pac-Man becomes very frustrating and it's pretty bare-bones to begin with.
In some other games I have reviewed (including the original Pac-Man), I have noted how terrible the d-pad on the 360's controller is. It's very unresponsive and in a game like Ms. Pac-Man, that leads to a lot of frustrating deaths. And when you add that to the fact that Namco is obviously taking a pretty lazy viewpoint of their games on Xbox Live, I question whether this game is even worth the money. Thankfully, the core game here is as solid as ever.
Ms. Pac-Man didn't exactly take the series in a completely new direction or anything. But it did add a few nice touches to the original Pac-Man that it was just enough of a change to make a difference. If you never cared for the original, however, Ms. Pac-Man will not change your mind. It's more difficult, but it looks better, the fruit moves around the maze, there are now many different mazes, etc. Oh and there are more interesting 'cut-scenes' this time around. Other than that, this is basically Pac-Man all over again.
I guess if you are a big fan of these games, like I am, then this might be worth a download. The game is still fun, even though the controller's problems will drive you nuts. And most of the achievements are pretty easy, for better or worse. So if you don't mind spending $5 on a bit of nostalgia, then I would give this a shot. Just don't go into it expecting anything new.