i use this.
tried numerous compressors before someone suggested this and it was by far the best.
it has clinical compression with no coloring, and with 4 knobs you have lot of control.
its a bit pricey though but dont regret getting it at all. its funny that ive spent the most for the pedal that "supposedly" does the less.
it works harder than all others though cause its always on.
now speaking of compression in general, i think that it is essential (especially for bad players like me) as it can drastically improve the way you perceive your sound. it feels as it makes the guitar itself sound better, not altering the tone but balancing the sonic combination of all strings together if you know what i mean