I've tried it on a bunch of sources like drums, bass, and vocals.. all very vibey. the two modes are very different and worth exploring. on top of the trashy compression you can get ala the level-loc, you can totally use this as a crunch/drive box. sounds really cool on bass and keys.
I've only had it for a few weeks, but in terms of actual usage I have it setup as a parallel send in a mix I'm working on where it's smacking my snare group (top and bottom). blending it back in the mix just right on the fader cracks the snare through real nice.
oto