Yeah, it doesn't help that Six Feet Under are rubbish either.
I think Barnes' vocals really changed from Eaten Back to Life to Butchered at Birth. On Eaten they were what I consider a really good sounding example of how I like death/thrash vocals, deep and aggresive but not overly gutteral. Then on Butchered he took them up a gear (or down as the case my be haha) and became one of the most instantly recognisable voices in death metal, I think. Man, the first four Cannibal records are CLASSICS.