Are you talking about the Vocal 300 harmonizer, or the pitch shifter in
the RP300A? The pitch shifter in my RP200 tracks well and is in tune. (The whammy effect, a different kind of pitch shifter, isn't in tune,
but that's a different story.)
You can hear samples of a couple of octave-shifted RP200 sounds at my website at: http://www.hunterharp.com/DigitechRP/ You'll see a bunch of folders there -- one of them is for sounds pitch-shifted down an octave. I think the stuff sounds in tune. See what you think.
Regards, Richard Hunter hunterharp.com