All of the polyphonic octave effects (the P in POG) as well as the Pitch Fork are digital and will provide a clean, glitch-free, fast-tracking octave down.

The Octave Multiplexer is an analogue circuit. These are monophonic. These tend to be a bit “dirty”. They tend to work best around a “sweet spot” on the guitar which is somewhere around the third fret up to the 12th fret. And tend to prefer one pickup over the other. Outside of that sweet spot, they can be “glitchy”. That’s just the way it is. That’s part of the charm of that effect. The octave down on the Micro Synth is also analogue.

If you want to be able to do bass harmonic intervals (double stops) or chords, then your only choice is digital, so you’re looking at one of the POGs or the Pitch Fork. If you want clean, glitch-free octave down across the entire range of your guitar, again you need to go digital. Will it sound exactly like a bass? No. With some additional filtering, you can get closer, but it will certainly allow you to play a very clean bass line. The Pitch Fork will also allow you to turn your guitar into a baritone guitar, a low-tuned guitar, or a requinto/guitalele.

I have seen many videos comparing the Micro POG, the Nano POG, and the Pitch Fork. They all do a great job with monophonic octave down bass lines. The Pitch Fork gives you by far the most flexibility. It’s an awesome machine. The Micro POG seems to have a slight edge over the Nano POG and the Pitch Fork for tracking chords to do things like 18 string guitar or organ sounds. It seems to track a bit faster and the algorithm seems better at balancing the notes in chords for a more natural sound. The Micro/Nano POGs allow you to control the balance between the octave up and the octave down. The Pitch Fork does not. It only allows you to control the balance between the effect and the dry signal when using the Up+Down setting, but the choice of intervals for the Up+Down setting is very musical and interesting. Of course the Micro/Nano POG only give you octaves.

So…bottom line. If you want flexibility to do things other than just bass lines, go with the Pitch Fork. It’s even the least expensive option. (???) If you want the fastest tracking and you know you’re only interested in octaves, go with the Micro POG. If you’re trying to save room on your pedalboard go for the Nano POG.

One more thing I forgot is that the Micro/Nano POGs have a separate effect out. This lets you send the dry signal to a guitar amp and the effect signal to a bass amp. It doesn’t switch between the two. You’ll always get the dry signal, but you could set the mix so that the bass amp would only be getting a signal when the effect is on.