Pixel-shifting is prone to some really terrible artifacting, particularly in shooting situations with movement (incl. any in-frame motion due to wind, etc.) Interestingly, whatever computational photography magic Panasonic is doing in the S1/S1R with their "multi-shot hi-res mode" appears to be far more robust in real-world shooting situations, even handheld. For those who care more about this, Lloyd Chambers has written extensive discussion and analysis of these systems at https://diglloyd.com/ (fair warning: access to the detailed analysis is part of the paid site, a few high-level notes are in the public blog).