You really should look up Nightwish.
As many here know, I am a Johnny Come Lately to ProgPower (IX was my first), and Nightwish last played here in 2003. I love Nightwish's sound, and Tarja was a big part of that. I have not listened to any of their stuff with Annette, yet. Epica and Delain, on the other hand, have been here recently and/or are coming soon.
This was not meant to be a "competition", and I recognized their differing styles when I offered up the post. I was just curious about how different folks around here viewed the offerings. I really appreciate the honest answers.
Given a choice to buy a newest release from either band, I'd probably choose "Both."