I've always disliked bands with screaming and growled vocals. It always seemed silly and false to me, especially with bands like Cradle of Filth who accompany it with a ridiculous goth image and cheesy effects. However, upon first listening to some Opeth, I was very impressed with the music. I was disappointed when the death vocals enterred but the song stuck with me and eventually I bought this album on impulse. After listening to it a couple of times I was hooked on it. The music is great in it's own right, but the death vocals are an integral part of the music. If he were singing instead, it wouldn't have the same effect, yet clean vocals are used effectively in parts, and it's incredible that the singer manages to growl so well and still keep his singing voice so smooth.
I think the artwork on Opeth's albums is a pretty good indicator of their style. It's dark and gothic, yet it's also intelligent and mature. I hesitate to describe Opeth as death metal because that gives the wrong impression. They have all the elements that death metal music has, but they sound so unlike any other band in that genre, they're really more than the sum of it's parts. The way they manage to write songs of around ten minutes on average without making them boring is very impressive. I thought Tool wrote long songs until I started listening to Opeth. But Opeth make songs that move all over the place, mostly with very smooth transitions, for long periods of time yet seem to last just a few minutes.
The only problem I have with this album is the track Dirge For November, which I think is quite dull, but it's just about the only dull Opeth song I've heard. The re-released version also comes with a bonus disc with two acoustic tracks that are probably only of interest to the more hardcore Opeth fans.
If you like the music but not the vocals, I still say buy this album (and this one inparticular), because the vocals will grow on you, and you may in fact come to like them.