For me it would be more Hetfield vs Dime. Dime was a flashy lead player, but I never felt over all he was that great as a lead. (though he had a few kick*** ones) As a rhythm guitarist who wrote grooving music. The only other guitarist I put in his league is Tony Iommi. That said, Hetfield later in his career started writing more grooving music starting on the Black album. Though he too was an extremely talented rhythm guitarist. Hell Dave Mustaine is right up there too. I was never a huge fan of Tony Iommi's lead either. When you talk Slayer, man. They wrote some completely different music. Driving riffs throwing in single note patterns in the middle of it. They were an entity all their own in style. Hammett is one of my all time favorite lead guitarist because his leads weren't all flash. They had their own life. His leads were like side journey during the song.