I really dig Slipknot. Saw the 'Disasterpieces' DVD and became a fan (in large part because of Joey's drumming
, but also becasue they put on a hell of a show. )
I can see why some don't like Vol. 3, because it's not as straight-up brutal as the first 2. But they have matured, and their sound has come a ways beyond the more 'simplistic' riffs of yesteryear. Like you point out, great arrangements, and the vox/songwriting have improved, I think.
They're like 2 sides of a coin... the first 2 albums are one type of musical idea, the 3rd is another. All together, they make a pretty compelling metal theme.
Just got the live album, and it kicks serious ass. Those guys are really tight.