Comparing Panorama Stitching Tools

Puma City, south elevation, PanoLab stitched puma city, south elevation, hugin stitched
puma city, south elevation, calico stitched Puma City, south elevation, single shot with 16MM lens

The above are the result of PanoLab, Hugin, Calico, and a single shot with a very wide angle lens (Canon’s 10-22mm, effectively 16mm on my Rebel XTi). The first three originated on my iPhone and the PanoLab shot was stitched and originally uploaded to Flickr on my iPhone (though I have since done some color enhancement and reuploaded the photo from my MacBook Pro). Hugin is GPL, the other solutions are less free (in both senses).