I'll have to disagree with !K_A! personally, as I thought their new stuff sucked ever since they put out 'Load', and 'Bigger Load' was even worse in my eyes. I've tested every album they've put out, because I respected the hell out of them when I listened to their older stuff, but none of the newer stuff holds a candle to their older stuff. They sold out for sure after the Black Album, it reminds me of the classic Samson story in the Bible, they lost all their power after they cut their hair (done between 'Metallica' and 'Load').

I don't have a whole lot of experience with Slayer (mostly listened to the album 'Reign in Blood' so far) but I like their sound. I've heard some newer songs (haven't analyzed em at all) but their sound did evolve without completely changing their style, which is the opposite of Metallica.

While I understand that artists may want to change their sound as they feel 'tapped out' on their original style and such, but if you don't like it, you don't like it.