In camera panorama?
I have used the Fuji version and it generates noticeable stitching errors.
It is a good feature if you are travelling, for instance, and want to post panoramic pics like the Arc de Triomphe from underneath without the hassle post-processing.
For other purposes you can get better panoramic results by stitching during the post-process stage.
Maybe the Sony and Panasonic versions are less error-prone, don't know.