This is based on another design by Look Mum No Computer. It uses a CoolAudio V3340D remake of the classic standalone VCO chip. It works well and has a pretty nice 1v/oct range.
I built this many years ago now, and I feel like there were some gotchas during the construction that I don't recall at this point. It is very fiddly to tune with the pots I used, so it's something I frequently will accidentally bump and then realize everything sounds like crap.
I've really come around to the benefits of digital VCOs in this regard. If you're gonna filter everything anyhow, there's not really any difference worth mentioning between the two, and with digital you get less drift and more options for less money and circuit complexity.