This is not tweakable, controllable dynamics, but is pretty much a try-it-and-see-if-it-works affair. I wouldn't take the dbx comparison too seriously, but applications seem to work in the neighborhood of what I here for the 163. It's not fantabulous, but not suck in normal mode. Compression is more aggressive than leveling. The cool trick to it is the input-level knob. Basically, instead of adjusting how hot the signal you're sending it is to tweak the threshold of the gain reduction, you have a cheater switch to lower the threshold. Which is pretty cool for being able to distress things a bit extra. Nuke compression sounds cool but undistinctive, unlike the compression on the Fostex MN-series mini mixers which is thick-but-bright/crunchy.
I've seen someone on the T-O forums compare the instrument-level compression to a Fairchild. I dunno, I haven't heard a Fairchild or plug-in emulation of it. If it's the case, I wouldn't shell out $30k for a Fairchild even if I had Bill Gates money. I view this as a decent, somewhat flexible comp to pick up on the cheap, one that serves a purpose, is sometimes even cool. If you mix analog, a good extra channel of cheap compression is handy. If you're in the box and sending stuff out for color, a good plug might do as well, and you get more instances.
Bear