Slayer
Best: Seasons In The Abyss
It combines the best of what two previous releases had.
Worst: there's no such thing as bad Slayer album :D, but if I had to choose - probably Diabolus In Musica, although I like it.
Megadeth
Best: Rust In Peace
My favourite of all time, what can I say more.
Worst: Risk
No surprise, huh?
Kreator
Best: Extreme Aggression
As the title says.
Worst: Cause For Conflict
Surprise, huh? :D To be honest, Endorama was close. I just can't convince to CFC.
Flotsam And Jetsam
Best: Doomsday For The Deceiver
Listen to the title…