Also never heard of this…
Downloaded the demo and clicked around a little. On first sight it looks a little like the combination of Zebra and SynthEdit. The semi-modular matrix approach from the first, the ability to build UIs and export instruments from the latter. Design and UI concept doesn’t seem to be fully up to u-he standards on first sight…
Probably no SDK though? This was what made SynthEdit great, the included modules were more for starting out…
Edit: Ok, the self-created instruments can only be used inside MSoundFactory, editing can be password protected etc. - so more like e.g. Kontakt or Reaktor than Synthedit then.
Edit 2: There is a four part video series about physical modelling on their web site. Neat!