It's a good $15,000 movie. The actors are good and the movie makes it's micro-budget a virtue. just don't go into it thinking you're going to see the Scariest Movie Ever, because it's not...not even close. the scares are effective, but they are primarily of the cheap "BOO!" variety and mostly telegraphed.
It had a better ending than BLAIR WITCH but mostly lacked BW's creepy factor.
And, to answer another post, yes I believe the ending was changed. Apparently the current ending was suggested by Steven Spielberg.