Pretty much a tie in my book. These are the 2 Testament CDs that I listen to the most these days. I prefer the production of "The Gathering", but if I had to pick ONE, I would have to go with "Low".
After the disappointing (in my opinion) CD "The Ritual", this was the kick in the ass that Testament needed to keep their loyal metalhead fans. At the time that it came out, the record industry was pushing for "Alternative" and Testament pretty much said "fuck you" and made a brutal "Metal" CD and have never looked back...