See Stereo.de
test (German) of the Rubicon 2. Look for 'Klirrfaktor' (distortion level). It's measured at 0.3% @ 63 Hz, which is an excellent result.
i-Fidelity has also done
measurements of several Dali speakers with SMC, but focus on impedance, frequency response and cumulative spectral decay (using waterfall graphs). Especially the latter proved excellent. Frequency response was decent but nothing special in the low and high range. Off-axis response was a bit better.
There's also the Stereophile review with
measurements of the Rubicon 8. Again, the frequently response is good but nothing special, with excellent results in the time domain.