I don't know man. The sun must have cooked your brane or something.
Metallica up to Justice was badass. I'll give them all the props in the world for that but let's look at releases.
1988 - And Justice For All
1988 - So Far So Good So What
Both great albums but So far is the more technical album.
1990 - Rust in Peace
1991 - Black Album
Enough fucking said.
1992 - Countdown to Extinction
Only half as good as Rust but still twice as good as Black album.
I loved Pantera when I was younger, saw them 6 times but Slayer and Anthrax are both far better bands.
Imagine being that wrong.
Metallica put a 4 album whooping on the Metal world from Kill em all through Justice. The Black album was their victory tour. Then they did their weird phase with load and reload. St anger was honestly their worst album but it was entirely redeemed by Death Magnetic. They made better music than Megadeth did throughout their entire career. Megadeth had its one redemption album with countdown, but overall they were the lesser band.
Also they tended to follow Metallica, so if you wanted an honest comparison I think it would look more like this.
Master of puppets vs So far So Good So What - Metallica Hands down
Justice Vs Rust - Uhhh Metallica
Black album Vs Countdown - I would say that countdown was the better metal album but the Black album was transcendent in terms of introducing new people to metal, and I would say that it actually made Countdown more famous simply because of the timing. Also, the number of mainstream hits on the black albums is rather astounding. I get that the hardcore fans were pissed about it, but it was not a sell out album, other than a sell out stadiums album maybe.
Lets not put Anthrax in the conversation with Pantera, that is just not ok.
I get there are Slayer fans and Pantera Fans, but I would say that while Slayer was the earlier more innovative band Pantera was the better band. I can listen to an entire Pantera album but every Slayer album gets repetitive.