The first and second games were awesome. Scared the living shit out of me. The third (the one in the mall) sucked to be honest. I never even knew a 4th came out, but by the way you described it, i wont be going out and getting it anytime soon.
I haven't played much of the third, I'm playing through the first right now. I'm in good ol' Midwich Elementary right now. But I liked what I played of the third. I'll play the second once I finish up the first.
But yeah, the fourth had nothing going for it except the music.