The Xotic SP features the same OTA (operational transconductance amplifier) technology as the Ross Compressor, so it provides the sort of squash familiar to many guitarists.
"There are internal DIP switches, giving access to four attack/ release options"
A three-way switch sets the strength of the compression, and there are internal DIP switches, giving access to four attack/ release options that add snap to the start of your note, a hi-cut filter and an input pad for high-powered humbuckers.
The best thing, though, is what you can dial in with the two knobs: an output volume knob with up to +15dB of boost and, something seen on few pedal compressors but very useful, a blend knob to give you dry sound mixed with the compressed.
Together, these enable you to use the pedal as a straight compressor but also as a nice-sounding booster with as little or as much compression as you want thrown in.
With the combination of boost and compression offering loads of options, this is a versatile addition to any 'board.