Team Plasma was okay. At least they were giving in an attempt, and was cool while carrying it out. Team Rocket was lame in most of their appearances in my opinion.
Team Galactic will probably always be at the top, because Cyrus was a hypnotic leader, a genius, and rich to begin with.
The only thing about about him is that he's a dark, confused soul who didn't really know what he was going to do, a.k.a. psycho.
But the charisma he had, and how everybody did what he said without question, and how he was a pinch away from achieving his goal of becoming God was the most awesome win ever in terms of evil teams.
That said, even if I think Team Plasma is decent, I think N is very awesome if not held together with Team Plasma. The trio, the two ladies, and N - all of them are beings out of this world, and for some reason, Geechisu doesn't feel like that at all.
Moreover, their theme, and specially N's theme is very awesome and dark sounding.