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.
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.