The ClinchFX EP+ is is based on the enormously successful ClinchFX EP-PRE.  The “front end” is a standard EP-PRE common-source JFET preamplifier which includes the ability to select EP-3 early or late serial number tones.  In the EP+ there is a second JFET boost stage, similar to the EP-PRE circuit, but with reduced output impedance.  Regardless of the reduced output impedance, this second stage is an active boost stage, not a unity gain buffer.
One advantage of reduced output impedance is that the EP+ can drive longer cable runs without losing high frequencies.
The internal charge-pump voltage doubler power supply allows the EP+ deliver up to 18db of clean boost.  The exact amount of boost available depends on how hard you drive the input of the EP+.  As with any amplifier circuit, excessive input levels will cause clipping, but when driven to clipping, the EP+ creates a softer type of clipping, unlike many other solid state circuits.
A big plus in using a boost stage instead of a buffer is that the pedal retains the tone enhancing qualities of the already successful EP-PRE.