Imagine if you will a couple of talented guitarists writing music over a period of a few years and all of a sudden they get to release an album (this is Opeth debut).
What you get here is almost a "best of" in a strange kind of way... to explain this you need to understand that Opeth tend to write chunks of songs, musical passages then bolt together their best moments to form rather long songs.
Sounds ugly and if most people tried it im sure it would be, however Opeth do it with such grace and brilliance you barely notice this as you just let the excellent musicianship flow over you.
Back to the plot, yes like a best of of all the best passages they wrote over 4-5 years before they got a record deal, and I would say a particularly important Opeth album to own. Both guitarists wrote the music on this album, something you dont get on later albums which is a shame because Peter does add an extra dimension to their already varied sound.
If you're an Opeth fan and youre wondering whether you need an album as old as this, trust me you do, theres a certain "untamed beauty" which has to some extent been polished out of Opeth... thats not to say theres anything wrong with new Opeth, it just feels completley free and rambling which makes it such a beauty.
If youre not sure about Opeth, never much heard of them they are really for anyone who loves modern metal, but just wishes it was more creative, more varied, more melodic, more... just MORE! If you understand what I mean, youll enjoy Opeth.