whenever did this "Big Four" of thrash metal come about, anyway? just for marketing's sake. I wonder how many diehard metalheads truly subscribe to the theory that those four are the cream of the crop. in the American "mainstream," maybe.
for me, Metallica have the longest peak of good music, but Reign In Blood trumps anything Metallica did (although obviously they are very different types of bands). Slayer started to go downhill around the same time Metallica did... mid-90s.
Megadeth have some good records but nothing that approaches the best from the other two.
And Anthrax have some good tunes but maybe 1 or 2 records I'd want to play all the way through.
I guess a Metallica/Slayer double bill would be pretty cool... if it was 1987 or something. would still be a bit jarring... they play at completely different speeds, and Metallica stretches things out and jams much much more than Slayer ever cared to. so they're not exactly a great musical pair...