The Mobius actually has a companion app that allows for input of the user’s head circumference and inter-aural arc measurements in order to tailor the headset’s HRTF and 3D virtualisation to something more personal. I have one.
I don’t have a Super X-Fi dongle (yet) but AFAIK, it uses uploaded photos of the user’s head and ears to the same intent and purpose. Which is more effective, remains to be seen. From early reports, the Super X-Fi app has multiple headphone profiles (Senn HD650 being one of them) and I would imagine that the effect will vary greatly depending on the profile used and whether that profile matches the headphone connected to the dongle. I would wager best results would be from matching profile with headphones. I would contend that the Mobius would at least have an advantage over headphones paired with a generic or mismatched Super X-Fi profile as far as HRTF goes.
My own experience, I found entering my measurements to be a significant improvement, albeit not quite a drastic one.
While better than by just using average, some circumference isn't enough for accurate HRTF.
There can be major variation in shape of similarly sized head, especially in face.
Also earlobes differ.
Only ways for really fully accurate HRTF are:
3D scanning whole head shape.
Or putting small mics into ears to record how sound from sources at different directions changes.
In those demonstrations during winter and spring Creative did that recording for improving image analyzing algorithm.
Need for any headphone compensation depends on accuracy of headphones.
Neutral and analytical headphones likely won't benefit from it really any.
Unlike some "warm" sound headphones, which really are just inaccurate in their reproduction of signal, muffling part of frequencies needed by binaural cues.