Ok, did a mini shootout through headphones because the kids are sleeping. MPG Level 4 with P/MM Nordstrand PU and Sadowsky preamp. The contenders:
1) Boss OC-2
2) Boss OC-3
3) MXR Bass Octave
4) Digitech BSW, mode 7
Last place is easily the MXR. Tracks terribly but I'm going to go back to it later because I remember it sounding pretty good before. I'll try with a different bass.
The Digitech sounds decent, but doesn't have the tone of the last two.
OC-3 sounds pretty good. The poly mode tracks very well but doesn't have the same classic oscillator sound of the OC-2 mode or the real OC-2. Many times I couldn't tell the difference between the OC-3 and the OC-2 when set similarly. Had a done a blind test, I'm not sure if I would have been able to score very high in the "Name that Pedal" game. I dislike the drive mode, YMMV.
The OC-2 sounds great, simple to use and tracks well as long as you stay away from open strings and reasonably high note-wise. I'm giving it the nod as the winner, but you really can't go wrong with the OC-3. I'll have to try an EBS at some point.