They are good in concert, though not because of any technical musical skill. They're just exciting performers. They're not bad musically, just not as technically gorgeous as some other bands(they're no Tool). Almost all current bands, in fact, are musical neanderthals compared to bands of the past like Pink Floyd or Rush. When it comes down to it, unless you're an arrogant Fascist, if the music's enjoyable it doesn't matter how elaborately technical it is. Of course, ultimately it's most desirable to hear perfectly organized music that is enjoyable as well, but that doesn't mean that sloppy enjoyable music can't be...enjoyed... as well.
No friggin clue what was up with the SNL debacle, but it may be a case like DMB's wherein quitting drugs/alcohol has a definate adverse effect on musical ability.
I do agree, though, that some of their stuff is utter nonsense. Even Korn's "Twist" is more provocative and intuitive than some of the garbled muck that SoaD produces.
Nevertheless in the midst of the muck there are some jewels.
I particularly enjoy Forest.