Hello,
I own an exar octavium, an octave Pedal.
It´s tracking is not superb but not that bad eighter.
I compared it yesterday to the aguilar octamizer, mxr octaver, the ehx POG, and the OC-3.
Trackingwise it is quite similar to the aguilar and the mxr. Soundwise its close to the MXR...