The Prince of Tone is about the same as half of the King of Tone, with an external MODE switch standard. The DISTORTION mode is improved though, for a louder, stronger distortion sound.

The TREBLE trimpot is inside, just like the KOT.
There are also two new DIP switches inside! They are a bit subtle at some knob settings and modes:
DIP1 : LO-MID lift switch. The tone from your lower strings will be enhanced a little.
DIP2: TURBO switch- with higher gain settings you’ll hear deeper compression, especially in DIST mode. You will hear a brighter, crunchier sound with this on at higher DRIVE settings.

The three modes are:
1) Normal Overdrive mode (OD mode): This is the standard King Of Tone sound, - a touch drive available than a tube screamer. Can get much louder than a tube screamer.
2) CLEAN mode : This mode has less distortion, it can be used for clean boosts or clearer, louder sounds. It's sort of a cross between a true clean boost and an overdrive. CLEAN MODE is even less compressed and louder than the OD mode. I love this mode with high drive settings too!
3) DISTORTION mode : more drive than the standard mode- a touch of hard distortion. The sound is more compressed, yet retains the pedal’s character. Same volume as OD mode.