Verified answer

I personally like Testament more.

I love Chucks voice. Tom Araya is to monotone.

Alex Skolnick is a better guitarist than Kerry King, even though King is pretty awesome too.

Practice What You Preach is a great song but Raining Blood is a f_cking classic. \m/ \m/ !!!!!!!

Slayer

Chuck Billy

Alex Skolnick

Raining Blood

Testament. More diverse and more consistent.

Chuck Billy. He has a much better range.

Alex Skonick. His solos are more well thought out.

Raining Blood. PWYP is a bit slowed down though it's still pretty good.

Slayer

Tom Araya

Kerry King

Raining Blood

Chuck Billy

Alex Skolnick

Raining Blood

It's hard for me to choose one over the other really I like em' both. =)

Slayer! of course, Slayer are in the big four of thrash too