I dunno. Kuja was certainly very evil, and even if he's a Sephiroth clone (with the silver hair), he's certainly got more aces up in his trumpet-like sleeves than Sephiroth has in his own. Kuja was evil because he was sane when he did all those horrible things to the poor people of Gaia (and your party for that matter....never want to see chain Flare Star combos ever AGAIN~~~!!!) and made planets explode. Sephiroth was just contented with blowing up one planet. But then again, Sephiroth couldn't be harmed by any sort of spell (remember that bit when Cloud had to accompany Sephiroth up Mt. Nibel and Cloud was this wussy, pathetic wimp who dies with one measly attack from any monster?!); the spells monsters cast on him had no effect whatsoever.

I actually like Kuja's poetic ramblings; he makes up for this classic psycho villain who just had to spout Shakespeare or something and be completely evil about it without really trying too hard. That makes him very intelligent. And he doesn't have to go all out on one battle; he is cold, calculating, and wouldn't do anything unless he has completely seen through all your strengths and weaknesses...and for a boss, that is a real recipe for disaster.

Sephiroth, on the other hand, is completely misunderstood. He just wants to find out if his existence wasn't just for nothing, that was why he has your FFVII party whacked out several times in the game. Then he kills Aerith. (I guess he can't stand anybody with more gorgeous hair than he has....:P) Then he goes challenging Jenova, and then ultimately, Cloud himself on that one on one battle.

Ultimecia's been hiding all throughout the game; first, she tries using Edea, then second, uses Rinoa to do her evil bidding. No wonder SeeDs were dispatched to control sorceresses because of the uncertainty that they may become all whacko. And that was why Ultimecia hated SeeDs; they made sure her plans were thwarted over and over again. But Ultimecia found a host in Matron, who eventually became Edea; in effect, she almost won (the SeeDs weren't existing yet). But then she made a complete mistake in controlling Rinoa. That's what made her hate SeeDs even more.

NECRON IS A WUSSY~~~!!!

Life is short.
Let's all grab a BEER~~~!!!