Okay. Got in some quality time with the SubT. As a basic octave pedal, no problem. I A/B'd it with my EBS octave pedal. Tracking is okay. (IMHO that's where a lot of octave pedals fall down.) Sound is good, and the filter control gives some tasteful options.
I re-watched the YouTube demo and used the settings shown as jump off points. The synth options are huge. Lots of combinations are available. It's very easy, though, to turn the sound into a buzzy distortion box. It takes some subtle tweaking to find some neat and useable synth sounds.
I was a bit disappointed at first try yesterday, but with time I'm finding my way to some useful stuff. A little synth goes a long way. I'll keep working with it, and for now it has a place on my board.
If I could make one suggestion, it would be to have the filter control work on the synth voices and not just the clean. That would give the option to tone down the wide open square, pulse and saw waves.
Tomorrow I'll see what I can do following the SubT with my Xero.