A legend in the Chicago underground music scene, David Grubbs is co-founder of heavily influential acts such as Squirrel Bait, Bastro and Gastr del Sol. Both Squirrel Bait and Bastro are among post-hardcore's initial breath (specially Bastro, some kind of artsier version of Big Black), while Gastr del Sol is some kind of subsequent canalized flow of artsiness from Bastro's members.
Since co-composing with genious music scientist Jim O'Rourke is surely ego demanding, parting ways was an expected step. The last Gastr del Sol's record, Camoufleur, is definitely mainly O'Rourke's, undoubtly different (better, as a matter of fact) from Upgrade and Afterlife. Not that the latter lacks of quality; it's their peak of conventional songwriting deconstruction - but obviously evolved from Mirror Repair and the first two, and obviously Grubbs' compositional trademark.
As a solo artist, Grubbs, at first, found himself as a lo-fi folk minimalist in 'Banana Cabbage, Potato Lettuce, Onion Orange', analog to some future Richard Young's Jagjaguwar albums (Sapphie, Making Paper and May). Later albums gradually became more unpretentious, specially in The Spectrum Between, a great example of what would became almost all of his Drag City records afterwards; Rickets and Scurvy and A Guess at the Riddle fit well to the style mentioned, while Off-Road and Act Five, Scene One are mostly experimental acts.