About the same as Testament's The New Order, though nowhere near as bad as When The Storm Comes Down, which I bought and soon sold. I don't know how it got past the band....
There seems to be some phasing in the vocals. And there are level issues with the guitars - especially being scooped mid, which was in full force in Metal - which may have been lack of track compression. Re-mixing and re-mastering (either album) might be enough. Relapse re-mastered Death's Human, which came out pretty well, though it's a toss-up between it and the original in listening experience.
Testament re-recorded a 'modern' version of Souls of Black some years ago. Sounds great on a small system, but loud the bass and kick get in the way of each other. I prefer the original in its form, though the newer version has cute nods to death metal of this century.