I've only heart Unquestionable Presence, but it's phenomenal.
GET AWAAAAAAAAY
DOOOON'T YOOOOOOU TOOOOOUUUUCCCHHHHH
MYYYYYYY PREEEEECIIIOOOOOOUUUUUSSSSS SHHHIIIIIPPPPP
BEEEEEE THHHAAAAAAANNNKKFUUUUUULLLLLL
YOOOOOUUUUUU EEEEVEEEEEENNN WIIIIITNEEEESEEEED IT AAAAAAAT ALLLLLLLKelly Schafer is probably one of my favorite vocalists of all time. Any genre, period. His voice is just total badassery and fits Atheist's sound perfectly. I can't wait for their fourth album
Get Piece of Time and Elements, see what you think. Piece of Time is more in the vein of early thrash metal with prog tendencies (Other than long songs, Atheist doesn't really do them, but I honestly think that it would really water their stuff down if they did that, they aren't that kind of band) thrown in here and there. Elements is the opposite, there's a full-on samba number on the album o_o. Its definitely their jazziest/most progressive album.
But all Atheist is fucking amazing, and I want to hear their next album soon enough. If it interests anyone, there's going to be a cover of YYZ on it. Yes, death metal cover of YYZ. Tell me that doesn't sound fucking awesome.