Octave up....

I have both the Pitchfork and the Sub n Up on my board. They do different things and both are worth having IMHO. That said, if all I wanted was a good sounding octave up, the Sub n Up sounds a bit more natural, the Pitchfork a bit more synth-like. Hope that helps.
 
Another vote for the Sub N Up!

The Toneprint Editor is freaking awesome. Right now I'm using a tweaked setting of the "OrganDonor" preset primarily for the up octave. I added a little flange and it's nice and moody. Great pedal.
 
I was searching for the most natural Up sound to feed delays/loops, before I settled on the Sub n'Up, the Digitec Whammy Ricochet was fun because of the momentary glissandi up or down, tracks well, but again synthy sounding like the Pitchfork and certainly the pog. Sub'nUp polyphonic setting is a great copy of a pog and the vintage sounds like OC2 (to me) but I use an organ patch too with some predelay on the octave.
 
You might also look at the TC Electronics Sub'n' Up. It works well for me. Nice octave up and down, and two octave down (no use on bass, really). The Tone Print feature adds versitility and has some practical and fun uploads -- a credible organ sound is one. I imagine you can edit your own Tone Print as well.
You can edit the tone prints--both in what parameters you set--but also for bass you can use the octave down controls to adjust otehr parameters if you aren't using them for octave down (That second octave down on a bass i very boomy---so not a lot of use for most situations)

I have one as well--and use it with my bass, guitar & mandolin. (On the mandolin I don't use the octave up)