I thought Perfect Dark was way overhyped and overrated. The plot is retarded, the enemies and characters are uninteresting, and most of the levels are really dull. There's a good variety of weapons, but some of them are pretty eyeroll-inducing.
To be fair, I don't give a damn about multiplayer, so I judged it purely for the single-player experience. (And I played the main campaign, unlike Gameguy here.)
This is the #2 N64 game on Metacritic, with a score of 97. That just blows my mind. In comparison, Medal of Honor and System Shock 2 both have a 92, No One Lives Forever a 91, and Deus Ex has a 90. To me, Perfect Dark doesn't hold a candle to those games.