It kinda shows that this wasn't made by the same people, both in a good and a bad way. The good news is that this movie seems to have regained some life since the last one, and it tries some new things instead of just going through the motions once more. The bad news is that said new things aren't necessarily better. In fact, this movie was even less funny than the already mediocre second outing, leaving it so far removed from the original that it feels like it shouldn't even be in the same series. Okay, there are some pretty funny moments, but it's never even close to being as clever as "The Naked Gun: From The Files From Police Squad!" or, for that matter, "Airplane!". Plus, the leading lady, already useless in the second movie, is now more annoying and cheesy than ever, somehow finding a way to make her age difference with Leslie Nielsen feel weirder than usual.
Basically, stick to the first movie from this series - ignore the rest.
In a sentence:
Continuing the decline in quality since the first film, this has some good moments but is marred by a convoluted plot, an annoying female lead and no remaining traces of cleverness.