I found Holbrooks to be front heavy when they were made of O-matter so I'll be curious how they manage to make the frame metal without adding too much weight. The nosebombs and Unobtanium on the earstems will help I suppose.
And yes, the Square O has been discontinued for over a year, but certain models retained it. Turbine switched since it was new, but for the Frogskins and Holbrook which are very popular, they've tried to introduce new models that were similar.