I'd have to say that I absolutely *love* Agalloch. I'd not compare them to Opeth, I mean.. like someone stated before -- yeah they do have that acoustic folk thing going occasionally, and the grim/clean vocals. But that's about it. To me, Agalloch has more black metal influences that shows in their sound.
I love the "simplistic" feel of Mantle. The recurring themes going across the entire album (Like when you hear the guitar lick reused from "A Celebration of the Death of Man" reused in "...And the Great Cold Death of the Earth"
The strongest songs on the album to me, well, just my favorites I guess, are "You Were But a Ghost in my Arms" and "Great Cold Death". I love the whole thing though, honestly. They recently released a limited vinyl press and it's for sale on theendrecords.com... I've contemplated buying it at least a dozen times.
I love the guys singing voice too (and I don't know his name, I confess to not doing much lineup research, even though I've been listening to them for a few years). I remember when I first found out about them, I showed their music to a friend of mine who I introduced to Opeth... and he thought "eh, it's ok" and then, I remember talking to him about a week later and he was completely hooked. Their music seems to really grow on you when you give it a chance.
Oh, and the end of "Odal" with the piano... man that sounds so depressing, but it's really pretty
And I really like the use of the Cello. However, I don't really like the last track that much. And that is probably the only one.
I can't count the times I've played "The Mantle" in its entirety.. and just laid down in bed listening (and normally falling asleep somewhere halfway) The music has so much more to it, when you shut out all your other senses.
I can't listen to it that much when I'm in an "upbeat" mood, because the music is so dark, it kind of drags you in...