The bellowing vocals aren't exactly my idea of professional singing, but they complement the propulsive riffs and add to the addictive qualities of the album.
"Suck" was too harsh a word, but the vocals are definitely the weak part of a very strong album. Actually it's only the lower grunt/growl vox that bug me, the clean and yelling ones are pretty alright. But the riffs, drums, and bass are pretty extra-ma-ordi-ma-nary.