The "suck" in Katatonia is the fact that they want to be a melancholy indie band, only without the good parts of melancholy indie music; things like, you know, CATCHY MELODIES. Watching a Katatonia show is truly catatonic. The only time you wake up is when you hear the classics.
It must be said, however, that Brave, Murder, and Day live are fucking awesome.
For me, the best "lite" metal band right now is Amorphis, hands down. End. Full stop. They've truly got something special.