Totally worth watching. Freaks you out with things that should not have been freaky. Shyamalan did a great job on this particular film and I suggest you download and watch it now, preferably with your computer/TV screen the only source of light in the room and you huddled under the covers all by your lonesome awaiting the horrors.
It was pretty shitty. Although I did enjoy the plot and finding out that the grad parents were actually slaughtered and the two so-called grandparents were escapees of a psych ward. With a more competent director I think it could have been an overall good film