they don't suck, and yes, they are still around. they did a tour recently, but les claypool (the brain behind them) does lots of other musical groups as well, so they haven't been especially productive for some years.
edit: everyone who has played with primus has been SUPER talented. claypool is a better bassist than flea, for example. one of their guitarists was trained by the amazing joe satriani, who's other students included the lead guitarist from metallica and steve vai. but primus writes quirky music with a very broad range, so i can see how people would be unable to appreciate them.
other lame musical trivia: joe satriani is/was friends with christopher guest ("nigel tufman" of Spinal Tap), and one of Joe's old guitars graces the cover of the DVD version of Spinal Tap.