EHX Pitch Fork will color your timbre more so than the Digitech Drop.
Digitech Drop is also true bypass.
PF doesn't do 3 semitones up/down, but Drop will do 3 down.
PF is also controllable with an expression pedal, which is what I use to make it my Whammy pedal.
The expression pedal/PF deal also lets me tune up down in increments that are not semitones, for instance a reference of 445 Hz vs. 440 Hz.
I use my Drop the most, because I'm usually playing C# Black Sabbath songs or some Eb Motörhead songs. I play both genres.
Don't get me wrong about the timbre coloring of the EHX, I actually like the way it sounds.
It's as if it adds some harmonics.
Also, the PF is pretty wild sounding if you put it in dual mode with an expression pedal.
Dual mode actually comes close to sounding like a chorus pedal, IMHO.