I think that Tarja did a great job with Nightwish. They made very beautiful music and the voice of Tarja fitted perfectly with the songs. But I heard that she became selfish, which was (in my opinion) inappropriate because it was Tuomas who wrote most of the songs (I think)Personally, I didn't like Anette: in the beginning, she sang off-key , even when the band put the songs in another key so that it became easier for her. She did improve, but for me, her voice wasn't "strong" enough for the songs. I once saw her live (I think last yeamr): she sang good but the rest of the performance was a bit weak: she almost didn't move (and if she did, she did a little weird dance-thing), almost no interaction with the public etc. It was a good concert, but it didn't leave a big impression on me(And now , Floor is the frontwoman of Nightwish, which seems like a big improvement to me)