It's a great addition to the Dead Space universe, but there's nothing tremendously exciting about it.
There's not a huge amount of "wow" to the game, but it wasn't disappointing in any way at all.
I had fun playing the game, and it actually did scare me, and probably will scare you too. It may not be worth a buy if you are uneasy about rail shooters, just a rental. But if you like rail shooters, I can safely say that you should go out and buy it, because it is most likely the best of its kind. I still recommend you try it out, because it left me very satisfied, and probably will with you too.