It does have it's flaws....but I wouldn't call it crap.
Some of my friends did though....
It doesn't hold up well to repeat viewings (mainly cause the ending doesn't make sense if you put it all back into the equation) and the movie has some serious timing/pacing issues and some slack dialogue but for a first time viewing it freaked me out and had me going "Oh shit!" quite a bit, so I'd still recommend it for a cheap thrill.
