Is the Harbinger One and R.G's Neovibe the same?
Close. Brian's has the modern mode and, I think, a couple common improvements scattered throughout the circuit. RG's schematic is a little tough to read (I mean, physically ... the colors, children!) so it's hard to directly compare at a glance. But all the mechanisms are the same -- same LFO etc.
Jon pretty much nailed it. The Harbinger is 95% Univibe (Neovibe). The added input buffer option gives it a different flavor. Plus, it fits perfectly in a horizontal 1590BB, which is nice.