The oc2 has the same issue broadly speaking.
There are a couple of alternatives, which are fairly easy to source. The ebs octabass, and mxr bass octave deluxe. (Loads of demo vids on YouTube)
These are the more common alternatives. ime, the ebs does a better 'smooth' octave, whereas the mxr will do better giving a slightly harder tone.
The pog is a digital octave, and can sound quite artificial. Some like it that way though, so horses for courses and all that!
Your best bet is to try as many as you can, and find that which floats your boat