Well, I'm not sure what to say about this one. It was both fantastic and horrible at the same time. It also was definitely not as good as Scary Movie 3 (and Scary Movie 3 was, actually, good, or at least I thought it was). We don't go to many movies, and I'm not sure why we picked this one - probably because it was my birthday week and I hold a long-standing love for Naked Gun and Leslie Nielson, but we made the most of it. The theater was full of loud entertaining 14-year olds, and as a precaution, a theater usher came in before the show and reminded everyone to be quiet - they responded by yelling at him that he sucked. They were actually pretty quiet during the show, though, so they must have liked it.
I guess I would recommend renting Scary Movie 4, if you're into that sort of thing, and not actually going to the theater so you can avoid all the 14-year olds and allow yourself the option of turning it off if it's not your thing. It may not be your thing.