There are some gems in there. ToTape6, FromTape, IronOxide5, Desk, HardVacuum, and the Channel series are nice flavors of saturation/distortion plugins. The Console series are a bit weird to set up but can do interesting things to a mix, though the effect is subtle. He's got a few really weird compressors (ButterComp, PyeWacket). GuitarConditioner is a lovely little distortion for some crunchy lead tones, which I believe is Tube Screamer inspired. He's also got some other little utility plugs (Coils, PowerSag2 come to mind) that can help enhance some guitar amp sim tones. He's also got a number of one-trick things that can be fun for weird sound design stuff.
I personally don't mind the (lack of) UI; too often, eye candy can be distracting, and at worst, it can even trick us into thinking a plugin sounds better than it actually does. The lack of visual feedback lends toward actually making decisions with my ears (fancy that, huh), which aligns with his philosophy anyway (an old tagline was "In mix, no one can hear your screen").
I also appreciate that his stuff is open source with a very permissive license.
Too many dithers, though. Jeez.
He is on the autism spectrum, which may or may not be a contributing factor to his particular presentation/documentation style.