Here's how they stack up as I see it:

[b]Resolution gain[/b]

No contest here, pixel shift will double the apparent pixel count on average whereas stitching can give you a tenfold increase or more (if you also focus stack).

[b]Automation[/b]

Pixel shift is largely automated (though not as much as some people would like), and takes a couple of seconds to complete. Capturing a panorama will typically take much longer and is a manual process that requires concentration. It can be automated but requires additional bulky hardware. 

[b]Tripod[/b]

Pixel shift requires a tripod, panoramas can be shot hand-held.

[b]Lens[/b]

Pixel shift is limited by the lens which will most likely drop off in sharpness at the borders. Panoramas can use the central portion of the lens only and can be razor sharp right to the extreme corners.

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