I'm still undecided on the clean vocals. I can see that in places clean vocals might sound quite nice with the music, and the harmonization is great, but I think they should've had a guest singer do them, as the singing isn't exactly great. I can imagine how they should sound, though, and I don't think it was an altogether bad idea.
The two opening tracks and the closer are the strongest ones on the album, I think, and The Lay of Autumn is also very beautiful, but the other songs don't stand out too much. I'd say about half of the album is unbelievable and the other half is just... pretty good. Which makes it still a worthwhile album, IMO.
This was only my first listen though so I'll need to hear it a few more times to be able to know what I really think about it.