OK, here's a first impression, after quite a few hours of burn-in and experimentation with assorted filters...
This thing is *good*, seriously good! It has a tonal weight that is really impressive, and adds to the "believability" that a R2R design usually has.
So far, my favourite filter setting is not what Ed recommended, so I kinda feel weird about it I'm using closed-form-fast, NS5.
Next, I'll try it with other servers/streamers, mostly to gauge the extent of SGM's contribution to the overall result...
2 days ago I spent a few hours listening to Formula and comparing it with other brands carried by the Aqua Hong Kong dealer.
SGMS was used as source.
IMHO Formula is at least on par with Totaldac Six, but each have its own characters and strong areas.
Very impressive!