A brief experience with the standard 80/2.8 Planar on a Rollei SL66 left me likewise disappointed with the rendition of out-of-focus areas. The OOF highlights were too "geometric," their shape resembled the hexagonal aperture of the lens, and OOF areas with lots of visual activity (I remember in particular a thin-DOF photo of some fallen leaves) had a very jarring feel. On the other hand, the in-focus areas on this lens were spectacular, and on most photos that's what really mattered!

So perhaps there's something about the 80mm Planar formulation that causes a distinctive bokeh signature across manufacturers implementations of this lens.